Run all linting in Docker via Dockerfile.lint (closes #109)

golangci-lint no longer runs on the host. script/lint builds
Dockerfile.lint, which copies the repo into the digest-pinned
golangci-lint image and lints as a build step, so a successful build is
a clean lint. The host binary shared one cache and one lock with every
other checkout on the machine, which produced findings attributed to
unrelated worktrees as well as unearned passes.

Three properties the wrapper has to get right:

- --no-cache-filter=lint forces the lint stage to re-execute. Without
  it an unchanged tree replays the layer and the build exits 0 in under
  a second having linted nothing. The deps stage stays cacheable.
- docker silently ignores --no-cache-filter when the stage name does
  not match, so the flag alone is a convention, not a guarantee: a
  rename or a typo restores the cached false green with no warning.
  script/lint therefore tees the build output and fails unless
  golangci-lint's own summary line ("N issues." / "N issues:") appears
  in it. No summary, no lint, whatever the exit code says.
- Both lint steps use RUN --network=none. golangci-lint config verify
  is documented as fetching its JSON schema over HTTPS; the pinned
  image resolves it with no network, and --network=none enforces that
  rather than trusting it. Verify is kept because golangci-lint run
  silently ignores config keys it does not recognize.

The main Dockerfile's lint stage now invokes golangci-lint directly
instead of `make lint`, which would otherwise need a docker daemon
inside the build.

golangci-lint installation is removed from script/bootstrap. Its curl
guard and its script/fetch-assets call are untouched.

Dockerfile

@@ -19,9 +19,14 @@ RUN go mod download
 # .dockerignore.
 COPY . .
 
-# Run formatting check and linter
+# Run formatting check and linter. golangci-lint is invoked directly rather
+# than through `make lint`: this stage is already the pinned linter image, and
+# script/lint is a wrapper that builds Dockerfile.lint, so calling it here
+# would need a docker daemon inside the build. Keep these steps in step with
+# Dockerfile.lint, including --network=none (see its header for why).
 RUN make fmt-check
-RUN make lint
+RUN --network=none golangci-lint config verify --config .golangci.yml
+RUN --network=none golangci-lint run --config .golangci.yml ./...
 
 # Build stage
 # golang:1.26.1-bookworm (Debian-based), 2026-03-17

Dockerfile.lint

@@ -0,0 +1,37 @@
+# Lint-only image, built by script/lint. golangci-lint is never installed on
+# the host: the repo is COPYed into the pinned image and linted as a build
+# step, so a successful build IS a clean lint. This works even when the docker
+# daemon is remote and bind mounts are impossible.
+#
+# script/lint passes --no-cache-filter=lint. Without it an unchanged tree
+# replays the lint stage from cache and the build succeeds in under a second
+# having run no linter at all. Do not drop that flag.
+#
+# The lint steps run with --network=none. `golangci-lint config verify` is
+# documented as fetching its JSON schema over HTTPS, which would make linting
+# depend on an unpinned remote artifact; this pinned image resolves the schema
+# without any network, and --network=none enforces that rather than trusting
+# it. It also proves no linter reaches out at analysis time. If a future image
+# bump makes either step need the network, this build fails loudly instead of
+# quietly acquiring an unpinned dependency.
+
+# golangci/golangci-lint:v2.12.2 (Debian-based), 2026-08-07
+# Using Debian-based image because mattn/go-sqlite3 (CGO) does not
+# compile on Alpine musl (off64_t is a glibc type).
+FROM golangci/golangci-lint:v2.12.2@sha256:5cceeef04e53efe1470638d4b4b4f5ceefd574955ab3941b2d9a68a8c9ad5240 AS deps
+
+WORKDIR /src
+
+# Copy go mod files first for better layer caching. This stage is cacheable;
+# only the lint stage below is forced to re-execute.
+COPY go.mod go.sum ./
+RUN go mod download
+
+FROM deps AS lint
+
+COPY . .
+
+# `run` silently ignores config keys it does not recognize, so a typo would
+# disable a setting without a word. `config verify` is what catches that.
+RUN --network=none golangci-lint config verify --config .golangci.yml
+RUN --network=none golangci-lint run --config .golangci.yml ./...

README.md

@@ -11,9 +11,16 @@ with retry support, logging, and observability. Category: infrastructure
 
 ### Prerequisites
 
-- Go 1.26+
-- golangci-lint v2.11+
-- Docker (for containerized deployment)
+- Go 1.26.1+ (the version in `go.mod`)
+- Docker (for linting, for the test stage of the CI gate, and for
+  containerized deployment)
+- `curl`, used by `script/fetch-assets` to download the third-party
+  browser assets, which are not committed (`make bootstrap` installs
+  it if missing)
+
+golangci-lint is not a prerequisite and must not be installed on the
+host: `script/bootstrap` does not install it, and `make lint` runs the
+digest-pinned linter image via `Dockerfile.lint`.
 
 ### Quick Start
 
@@ -22,14 +29,18 @@ with retry support, logging, and observability. Category: infrastructure
 git clone https://git.eeqj.de/sneak/webhooker.git
 cd webhooker
 
-# Install Go dependencies
-make deps
+# Install Go dependencies and the third-party browser assets.
+# `make deps` alone is not enough: it only runs go mod download/tidy,
+# and the checks below need the fetched assets.
+make bootstrap
 
-# Run all checks (format, lint, test, build)
+# Run all checks (test, lint, format check)
 make check
 
-# Run in development mode (uses SQLite in current directory)
-make dev
+# Run in development mode. DATA_DIR defaults to /var/lib/webhooker in
+# every environment, so set it (in .env or the shell) to a writable
+# directory when running from a clone.
+DATA_DIR=./data make dev
 
 # Build Docker image
 make docker
@@ -42,13 +53,18 @@ make bootstrap  # Install all dependencies (idempotent)
 make setup      # Bootstrap + install git pre-commit hook
 make assets     # Fetch + verify third-party browser assets
 make fmt        # Format code (gofmt + goimports)
-make lint       # Run golangci-lint
+make fmt-check  # Fail if gofmt would change anything (writes nothing)
+make lint       # Run golangci-lint in Docker (Dockerfile.lint)
 make test       # Run tests with race detection
 make check      # test + lint + fmt-check (CI gate)
 make build      # Build binary to bin/webhooker
+make run        # build, then run ./bin/webhooker
 make dev        # go run ./cmd/webhooker
+make deps       # go mod download + go mod tidy
 make docker     # Build Docker image
 make hooks      # Install git pre-commit hook that runs script/precommit
+make css        # Regenerate static/css/tailwind.css (needs tailwindcss)
+make clean      # Remove bin/
 ```
 
 ### Configuration
@@ -90,7 +106,7 @@ TTY detection, and security headers are always applied.
 | `PORT`                  | HTTP listen port                    | `8080`   |
 | `DATA_DIR`              | Directory for all SQLite databases  | `/var/lib/webhooker` |
 | `DEBUG`                 | Enable debug logging                | `false`  |
-| `MAINTENANCE_MODE`      | Serve the maintenance page          | `false`  |
+| `MAINTENANCE_MODE`      | Report `maintenanceMode: true` in the healthcheck JSON. It does not change how any request is served — no maintenance page exists | `false`  |
 | `METRICS_USERNAME`      | Basic auth username for `/metrics`  | `""`     |
 | `METRICS_PASSWORD`      | Basic auth password for `/metrics`  | `""`     |
 | `SENTRY_DSN`            | Sentry error reporting DSN          | `""`     |
@@ -130,8 +146,13 @@ sustained trickle re-locks them immediately.
 
 The remedy is to set `TRUSTED_PROXIES` to your reverse proxy's
 address, which restores per-client buckets. webhooker logs a warning
-at startup when `WEBHOOKER_ENVIRONMENT=prod` and `TRUSTED_PROXIES` is
-empty. See [Rate Limiting](#rate-limiting) for what each limit shares.
+at startup whenever `TRUSTED_PROXIES` is empty, in every environment —
+not only when `WEBHOOKER_ENVIRONMENT=prod`, because that variable
+defaults to `dev` and an operator who never set it is precisely the
+one at risk. The warning is informational when nothing proxies to the
+process: with no proxy in front, the peer address is the client's own
+and the buckets are already per-client. See
+[Rate Limiting](#rate-limiting) for what each limit shares.
 
 `X-Real-IP` and `True-Client-IP` are **never** read, from any peer.
 Reverse proxies append to `X-Forwarded-For` but forward other client
@@ -163,6 +184,8 @@ Two operator requirements follow:
   makes all three limits, including the unauthenticated webhook
   receiver, silently bypassable by every client in the block.
 
+#### Sessions
+
 Sessions are bounded by two independent clocks, and end at whichever
 one runs out first:
 
@@ -232,17 +255,20 @@ docker run -d \
 The container runs as a non-root user (`webhooker`, UID 1000), exposes
 port 8080, and includes a health check against
 `/.well-known/healthcheck`. The `/var/lib/webhooker` volume holds all
-SQLite databases: the main application database (`webhooker.db`) and
-the per-webhook event databases (`events-{uuid}.db`). Mount this as a
-persistent volume to preserve data across container restarts.
+SQLite databases: the main application database (`webhooker.db`), the
+per-webhook event databases (`events-{uuid}.db`), and any archive
+databases written by `database` targets (`archive-{uuid}.db`). Mount
+this as a persistent volume to preserve data across container
+restarts.
 
 ## Entrypoints
 
 This repository adheres to the
 [Scripts to Rule Them All](https://github.com/github/scripts-to-rule-them-all)
 standard: normalized scripts in `script/` are the entrypoints for the
-development workflow, and the Makefile targets are thin shims that call
-them. We provide:
+development workflow. Ten of the Makefile's sixteen targets are thin
+shims that call them; `build`, `run`, `dev`, `deps`, `clean` and `css`
+are inline commands with no script behind them. We provide:
 
 - `script/bootstrap` — install all dependencies (idempotent)
 - `script/setup` — make a fresh clone ready for development
@@ -251,7 +277,7 @@ them. We provide:
 - `script/fetch-assets` — download the third-party browser assets into
   `static/`, verifying each against its pinned sha256
 - `script/test` — run the test suite
-- `script/lint` — run golangci-lint
+- `script/lint` — run golangci-lint in Docker (see Linting below)
 - `script/fmt` — format all code (writes)
 - `script/fmt-check` — check formatting (read-only)
 - `script/check` — run test, lint, and fmt-check
@@ -354,7 +380,11 @@ It uses:
 - **[gorilla/csrf](https://github.com/gorilla/csrf)** for CSRF
   protection (cookie-based double-submit tokens)
 - **[go-chi/httprate](https://github.com/go-chi/httprate)** for
-  per-IP login rate limiting (sliding window counter)
+  sliding-window rate limiting of the login, password-change and
+  webhook receiver endpoints. The bucket is per client IP only when
+  `TRUSTED_PROXIES` names the reverse proxy; unset, every client
+  behind that proxy shares one bucket per limit (see
+  [Rate Limiting](#rate-limiting))
 - **[Prometheus](https://prometheus.io)** for metrics, served at
   `/metrics` behind basic auth
 - **[Sentry](https://sentry.io)** for optional error reporting
@@ -372,7 +402,7 @@ The codebase uses consistent naming throughout (rename completed in
 
 ### Data Model
 
-webhooker's data model has eight entities organized into two tiers: the
+webhooker's data model has nine entities organized into two tiers: the
 **application tier** (user and webhook configuration) and the **event
 tier** (event ingestion, delivery, and logging).
 
@@ -464,9 +494,25 @@ days (`database.RetentionForeverDays`). The retention reaper recognises
 that sentinel and skips the webhook entirely, and the web UI displays
 such a webhook's retention as "forever" rather than as a day count.
 
-A *finite* retention is capped at `database.MaxFiniteRetentionDays`
-(106751 days, about 292 years), and a larger one is rejected with a
-400. The cap is not arbitrary: the reaper computes its cutoff as a
+Submitted `retention_days` values therefore fall into three bands, not
+two:
+
+- `1` up to `database.MaxFiniteRetentionDays` (106751 days, about 292
+  years) is accepted as a finite retention.
+- Above that ceiling but below the retain-forever sentinel of 365000
+  (`database.RetentionForeverDays`) is rejected with a 400. This is the
+  band the cap exists for.
+- `0`, and `365000` or above, are accepted and mean retain forever,
+  collapsing to the sentinel — `0` in `Webhook.BeforeSave`, the large
+  values in `parseRetentionDays`. The large values are not out of
+  range: the edit form pre-fills the sentinel for a retain-forever
+  webhook, so submitting that form back unchanged has to keep meaning
+  "forever".
+
+A negative value is in none of the three: `parseRetentionDays` rejects
+it with a 400 before `BeforeSave` ever sees it.
+
+The cap is not arbitrary: the reaper computes its cutoff as a
 `time.Duration`, an int64 nanosecond count, and a longer period
 overflows it. An overflowed cutoff lands in the future, where it
 matches every row, so the sweep would delete every event the webhook
@@ -484,7 +530,7 @@ the full request and creates an Event.
 | -------------- | ------- | ----------- |
 | `id`           | UUID    | Primary key |
 | `webhook_id`   | UUID    | Foreign key → Webhook |
-| `path`         | string  | Unique URL path (UUID-based, e.g. `/webhook/{uuid}`) |
+| `path`         | string  | Unique bare UUID, generated at creation. The `/webhook/` prefix is route only and is not stored: the receiver matches this column against the raw `{uuid}` path segment |
 | `description`  | string  | Optional description |
 | `active`       | boolean | Whether this entrypoint accepts events (default: true) |
 
@@ -508,8 +554,8 @@ events should be forwarded.
 | `type`           | TargetType | One of: `http`, `slack`, `database`, `log` |
 | `active`         | boolean    | Whether deliveries are enabled (default: true) |
 | `config`         | JSON text  | Type-specific configuration |
-| `max_retries`    | integer    | Maximum retry attempts for HTTP targets (0 = fire-and-forget, >0 = retries with backoff) |
-| `max_queue_size` | integer    | Maximum queued deliveries (for HTTP targets with retries) |
+| `max_retries`    | integer    | Maximum retry attempts for `http` and `slack` targets (0 = fire-and-forget, >0 = retries with backoff and a circuit breaker). Ignored by `database` and `log` targets |
+| `max_queue_size` | integer    | Stored and shown on the target's detail view, but not enforced anywhere yet: nothing in the delivery engine consults it. Queue depth is set by the two fixed 10,000-entry channels |
 
 **Relations:** Belongs to Webhook. Has many Deliveries.
 
@@ -522,6 +568,11 @@ events should be forwarded.
   greater than 0, failed deliveries are retried with exponential backoff
   up to `max_retries` attempts, protected by a per-target circuit
   breaker.
+- **`slack`** — Post the event as a formatted message to a
+  Slack-compatible incoming webhook URL (`webhookUrl` in `config`). It
+  is built on the same HTTP core as `http` and honours `max_retries`
+  identically, circuit breaker included. See the Slack target section
+  under "Per-Webhook Event Databases" for the message format.
 - **`database`** — Archive the full event as a row into a separate
   per-webhook archive database (`archive-{webhookID}.db`) for long-term
   retention, with an optional creation-validated expiry (default: keep
@@ -558,7 +609,7 @@ data for auditing and for the planned replay capability.
 | `id`             | UUID   | Primary key |
 | `webhook_id`     | UUID   | Foreign key → Webhook |
 | `entrypoint_id`  | UUID   | Foreign key → Entrypoint |
-| `method`       | string | HTTP method (POST, PUT, etc.) |
+| `method`       | string | HTTP method of the captured request. Always `POST`: the receiver answers every other method with 405 before an Event is created |
 | `headers`      | JSON   | Complete request headers |
 | `body`         | text   | Raw request body |
 | `content_type` | string | Content-Type header value |
@@ -613,7 +664,9 @@ retries) is individually logged for full observability.
 
 #### Common Fields
 
-All entities include these fields from `BaseModel`:
+Every entity except `Setting` includes these fields from `BaseModel`.
+`Setting` is a bare key-value row with no `id`, no timestamps and no
+soft delete:
 
 | Field        | Type      | Description |
 | ------------ | --------- | ----------- |
@@ -659,7 +712,7 @@ handles connection pooling, lazy opening, migrations, and cleanup.
 This separation provides:
 
 - **Isolation** — a high-volume webhook won't cause lock contention or
-  WAL bloat affecting the main application or other webhooks.
+  journal growth affecting the main application or other webhooks.
 - **Independent lifecycle** — event databases can be independently
   backed up, archived, rotated, or size-limited without impacting the
   application.
@@ -669,9 +722,12 @@ This separation provides:
 - **Per-webhook retention** — the `retention_days` field on each webhook
   controls automatic cleanup of old events in that webhook's database
   only, or disables cleanup entirely when set to `0` (retain forever).
-- **Performance** — each webhook's database has its own WAL, its own
-  page cache, and its own lock, so concurrent event ingestion across
-  webhooks won't contend.
+- **Performance** — each webhook's database has its own page cache and
+  its own lock, so concurrent event ingestion across webhooks won't
+  contend. No write-ahead log is involved: both DSNs are
+  `file:{path}?cache=shared&mode=rwc` and no `journal_mode` pragma is
+  ever issued, so every database runs on SQLite's default rollback
+  journal.
 
 The **database target type** builds on this architecture to provide
 long-term archiving, separate from the per-webhook event database (which
@@ -727,8 +783,9 @@ and other compatible services). Each message includes event metadata
 pretty-printed in a code block. JSON payloads are automatically
 formatted with indentation for readability; non-JSON payloads are shown
 as raw text. Large payloads are truncated to keep messages reasonable.
-Config stores `webhook_url` — the Slack/Mattermost incoming webhook
-endpoint.
+Config stores `webhookUrl` — the Slack/Mattermost incoming webhook
+endpoint. That is the JSON key; the error text for a missing one reads
+`webhook_url is required`, which is the message, not the key.
 
 The database uses the
 [modernc.org/sqlite](https://pkg.go.dev/modernc.org/sqlite) driver at
@@ -750,8 +807,9 @@ External Service
                      1. Look up Entrypoint by UUID
                      2. Capture full request as Event
                      3. Create Delivery records for each active Target
-                     4. Build self-contained DeliveryTask structs
-                        (target config + event data inline for ≤16KB)
+                     4. Build self-contained delivery.Task structs
+                        (target config + event data inline for
+                         bodies < 16 KiB)
                      5. Notify Engine via channel (no DB read needed)
                                                 │
                                                 ▼
@@ -786,7 +844,7 @@ at any time, preventing goroutine explosions regardless of queue depth.
   a delivery channel (new tasks from the webhook handler) and a retry
   channel (tasks from backoff timers). Both are buffered to 10,000.
 - **Fan-out via channel, not goroutines:** When an event arrives with
-  multiple targets, each `DeliveryTask` is sent to the delivery channel.
+  multiple targets, each `delivery.Task` is sent to the delivery channel.
   Workers pick them up and process them — no goroutine-per-target.
 - **Worker goroutines:** A fixed number of worker goroutines select from
   both channels. Each worker processes one task at a time, then picks up
@@ -810,7 +868,12 @@ This means:
 - **Independent results** — each worker records its own delivery result
   in the per-webhook database without coordination.
 - **Graceful shutdown** — cancel the context, workers finish their
-  current task and exit. `WaitGroup.Wait()` ensures clean shutdown.
+  current task and exit. The stop hook waits for the pool via
+  `lifecycle.WaitForShutdown`, which bounds that wait by fx's stop
+  timeout rather than blocking forever on a wedged worker. On timeout
+  it logs at `ERROR` and returns an error, and the goroutines that
+  did not finish are still running — an unclean shutdown is reported
+  rather than hidden.
 
 **Recovery paths:**
 
@@ -838,12 +901,13 @@ remains stored in the per-webhook event database, there is no way to
 redeliver it: manual redelivery is planned, not implemented (see
 [TODO.md](TODO.md)).
 
-### Circuit Breaker (HTTP Targets with Retries)
+### Circuit Breaker (HTTP and Slack Targets with Retries)
 
-HTTP targets with `max_retries` > 0 are protected by a **per-target circuit breaker** that
-prevents hammering a down target with repeated failed delivery attempts.
-The circuit breaker is in-memory only and resets on restart (which is
-fine — startup recovery rescans the database anyway).
+`http` and `slack` targets with `max_retries` > 0 are protected by a
+**per-target circuit breaker** that prevents hammering a down target
+with repeated failed delivery attempts. The circuit breaker is
+in-memory only and resets on restart (which is fine — startup recovery
+rescans the database anyway).
 
 **States:**
 
@@ -879,10 +943,12 @@ fine — startup recovery rescans the database anyway).
 - **Failure threshold:** 5 consecutive failures before opening
 - **Cooldown:** 30 seconds in open state before probing
 
-**Scope:** Circuit breakers only apply to **HTTP targets with
-`max_retries` > 0**. Fire-and-forget HTTP targets (`max_retries` == 0),
-Slack targets, database targets (local operations), and log
-targets (stdout) do not use circuit breakers.
+**Scope:** Circuit breakers apply to **`http` and `slack` targets with
+`max_retries` > 0**. The Slack target is built on the same HTTP core
+and hands its own `max_retries` to the same retry path, so it gets a
+breaker with the same 5-failure / 30-second defaults. Fire-and-forget
+targets of either type (`max_retries` == 0), database targets (local
+operations), and log targets (stdout) do not use circuit breakers.
 
 When a circuit is open and a new delivery arrives, the engine marks the
 delivery as `retrying` and schedules a retry timer for after the
@@ -898,9 +964,11 @@ unpredictable rates, and blanket limits shared with other routes would
 cause legitimate deliveries to be dropped.
 
 The receiver instead has its own dedicated abuse limit, scoped to the
-`/webhook/{uuid}` route only and keyed per client IP per entrypoint: one
-misbehaving sender is throttled without affecting other senders of the
-same entrypoint or the same sender's other entrypoints. The limit is
+`/webhook/{uuid}` route only and keyed per client IP per request path
+(`httprate.KeyByEndpoint`): one misbehaving sender is throttled without
+affecting other senders of the same entrypoint or the same sender's
+other entrypoints. Keying on the path rather than on the entrypoint
+matters — see the aggregate limit below. The limit is
 `RECEIVER_RATE_LIMIT` requests per minute (default 120, generous for
 legitimate webhook senders). Requests over the limit receive HTTP 429
 with a `Retry-After` header. A set-but-invalid `RECEIVER_RATE_LIMIT`
@@ -935,7 +1003,14 @@ Every limiter here — receiver, login, and password change — identifies
 the client the same way, through one shared key function: the
 connection's own address, unless the peer is listed in
 `TRUSTED_PROXIES`, in which case the forwarded client address is used
-instead. See [Trusted proxies](#trusted-proxies). Deployed without that
+instead. That address becomes a bucket by family: IPv4 keys on the full
+address, IPv6 on its `/64` prefix. A routed `/64` is the normal
+residential and mobile IPv6 allocation, so keying IPv6 per address would
+let one subscriber rotate source addresses and mint a fresh bucket per
+request, evading these limits at the network layer without spoofing
+anything; the cost is that distinct clients inside one `/64` share a
+bucket. IPv4-mapped addresses (`::ffff:1.2.3.4`) key as the IPv4 address
+they carry. See [Trusted proxies](#trusted-proxies). Deployed without that
 variable set, a client behind a reverse proxy shares one bucket with
 every other client behind the same proxy. Set `TRUSTED_PROXIES` to the
 proxy's address to get per-client limits back. What the shared bucket
@@ -958,8 +1033,8 @@ opposite directions:
   login bucket full, and the operator's own login returns HTTP 429 for
   as long as that trickle continues. A restart clears the in-memory
   buckets and a resumed trickle re-locks them. Production deployments
-  must set `TRUSTED_PROXIES`; webhooker warns at startup when it is
-  empty in `prod`.
+  must set `TRUSTED_PROXIES`; webhooker warns at startup whenever it is
+  empty, in any environment.
 
 Finer-grained per-webhook rate limits (configured in the web UI and
 enforced in the webhook handler) can layer on top of this env-level
@@ -971,17 +1046,17 @@ abuse limit later; they are tracked as future work.
 
 | Method | Path                        | Description |
 | ------ | --------------------------- | ----------- |
-| `GET`  | `/`                         | Root redirect (authenticated → `/sources`, unauthenticated → `/pages/login`) |
-| `GET`  | `/.well-known/healthcheck`  | Health check (JSON: status, uptime, version) |
-| `GET`  | `/s/*`                      | Static file serving (embedded CSS, JS) |
-| `ANY`  | `/webhook/{uuid}`           | Webhook receiver endpoint (accepts all methods) |
+| `GET`  | `/`                         | Root redirect, 303 (authenticated → `/sources`, unauthenticated → `/pages/login`) |
+| `GET`  | `/.well-known/healthcheck`  | Health check (JSON: `status`, `now`, `uptimeSeconds`, `uptimeHuman`, `version`, `appname`, `maintenanceMode`) |
+| any    | `/s/*`                      | Static file serving (embedded CSS, JS). Mounted for every method, not just `GET`/`HEAD`: chi's `Mount` registers all methods and `http.FileServer` special-cases only `HEAD` (by omitting the body), so a `POST` or `DELETE` to an asset is answered `200` with the file. Pinned by `TestStaticServesEveryMethod` |
+| `POST` | `/webhook/{uuid}`           | Webhook receiver endpoint. `POST` only — every other method is answered `405 Method Not Allowed` with `Allow: POST`. Rate limited (see [Rate Limiting](#rate-limiting)) |
 
 #### Authentication Endpoints
 
 | Method | Path            | Description |
 | ------ | --------------- | ----------- |
-| `GET`  | `/pages/login`  | Login page |
-| `POST` | `/pages/login`  | Login form submission |
+| `GET`  | `/pages/login`  | Login page (not rate limited; the limiter applies to POST only) |
+| `POST` | `/pages/login`  | Login form submission (5 per minute per bucket, then 429) |
 | `POST` | `/pages/logout` | Logout (destroys session) |
 
 #### Authenticated Endpoints
@@ -989,6 +1064,7 @@ abuse limit later; they are tracked as future work.
 | Method | Path                     | Description |
 | ------ | ------------------------ | ----------- |
 | `GET`  | `/user/{username}`       | User profile page |
+| `POST` | `/user/{username}/password` | Change the user's password (5 per minute per bucket, then 429) |
 | `GET`  | `/sources`               | List user's webhooks |
 | `GET`  | `/sources/new`           | Create webhook form |
 | `POST` | `/sources/new`           | Create webhook submission |
@@ -998,13 +1074,17 @@ abuse limit later; they are tracked as future work.
 | `POST` | `/source/{id}/delete`    | Delete webhook |
 | `GET`  | `/source/{id}/logs`      | Webhook event logs |
 | `POST` | `/source/{id}/entrypoints` | Add entrypoint to webhook |
+| `POST` | `/source/{id}/entrypoints/{entrypointID}/delete` | Delete an entrypoint |
+| `POST` | `/source/{id}/entrypoints/{entrypointID}/toggle` | Enable or disable an entrypoint |
 | `POST` | `/source/{id}/targets`   | Add target to webhook |
+| `POST` | `/source/{id}/targets/{targetID}/delete` | Delete a target |
+| `POST` | `/source/{id}/targets/{targetID}/toggle` | Enable or disable a target |
 
 #### Infrastructure Endpoints
 
 | Method | Path       | Description |
 | ------ | ---------- | ----------- |
-| `GET`  | `/metrics` | Prometheus metrics (requires basic auth) |
+| `GET`  | `/metrics` | Prometheus metrics, behind basic auth. The route is registered only when `METRICS_USERNAME` is set; otherwise it does not exist and returns 404 |
 
 #### API (Planned)
 
@@ -1018,8 +1098,10 @@ abuse limit later; they are tracked as future work.
 | `GET`    | `/api/v1/webhooks/{id}/events` | List events for webhook |
 | `POST`   | `/api/v1/events/{id}/redeliver`| Redeliver an event |
 
-API authentication will use API keys passed via `Authorization: Bearer
-<key>` header.
+None of these exist yet. `/api/v1` is mounted with no routes, so every
+path under it returns 404 today. API authentication will use API keys
+passed via `Authorization: Bearer <key>` header; no Bearer middleware
+is implemented either.
 
 ### Package Layout
 
@@ -1047,16 +1129,30 @@ webhooker/
 │   │   ├── model_delivery_result.go  # DeliveryResult entity (per-webhook DB)
 │   │   ├── model_apikey.go    # APIKey entity
 │   │   ├── password.go        # Argon2id hashing and verification
+│   │   ├── retention.go       # Retention reaper (per-webhook event expiry)
+│   │   ├── testing.go         # NewTestDatabase: wrapper for tests, no fx lifecycle
 │   │   └── webhook_db_manager.go  # Per-webhook DB lifecycle manager
 │   ├── globals/
 │   │   └── globals.go         # Build-time variables (appname, version, arch)
 │   ├── delivery/
 │   │   ├── engine.go          # Event-driven delivery engine (channel + timer based)
-│   │   ├── circuit_breaker.go # Per-target circuit breaker for HTTP targets with retries
+│   │   ├── circuit_breaker.go # Per-target circuit breaker for http/slack targets with retries
+│   │   ├── target.go          # Target interface, Task, Scheduler
+│   │   ├── target_http.go     # HTTP target (retries, circuit breaker)
+│   │   ├── target_slack.go    # Slack/Mattermost incoming-webhook target
+│   │   ├── target_database.go # Database archive target
+│   │   ├── target_database_archive.go  # Archive file lifecycle and pruning
+│   │   ├── target_log.go      # Log target (stdout)
+│   │   ├── target_config_view.go  # Masked target config for templates
+│   │   ├── archive_sweeper.go # Periodic pruning of idle archives
+│   │   ├── url_mask.go        # Strips credentials from *url.Error
 │   │   └── ssrf.go            # SSRF prevention (IP validation, safe HTTP transport)
+│   ├── lifecycle/
+│   │   └── lifecycle.go       # Shared fx start/stop hook helpers
 │   ├── handlers/
 │   │   ├── handlers.go        # Base handler struct, JSON helpers, template rendering
 │   │   ├── auth.go            # Login, logout handlers
+│   │   ├── event_log_view.go  # Event log projection, byte-capped in SQL
 │   │   ├── healthcheck.go     # Health check handler
 │   │   ├── index.go           # Index page handler
 │   │   ├── profile.go         # User profile handler
@@ -1069,20 +1165,28 @@ webhooker/
 │   ├── middleware/
 │   │   ├── middleware.go      # Logging, CORS, Auth, Metrics, MetricsAuth, SecurityHeaders, MaxBodySize
 │   │   ├── csrf.go            # CSRF protection middleware (gorilla/csrf)
-│   │   └── ratelimit.go       # Per-IP rate limiting middleware (go-chi/httprate)
+│   │   ├── ratelimit.go       # Per-IP rate limiting middleware (go-chi/httprate)
+│   │   └── testing.go         # NewForTest: Middleware without the fx lifecycle
 │   ├── server/
 │   │   ├── server.go          # Server struct, fx lifecycle, signal handling
 │   │   ├── http.go            # HTTP server setup with timeouts
 │   │   └── routes.go          # All route definitions
 │   └── session/
-│       └── session.go         # Cookie-based session management
+│       ├── session.go         # Cookie-based session management
+│       └── testing.go         # NewForTest: Session without the fx lifecycle
 ├── static/
 │   ├── static.go              # //go:embed directive
-│   ├── css/style.css          # Custom stylesheet (system font stack, card effects, layout)
-│   └── js/app.js              # Client-side JavaScript (minimal bootstrap)
-├── templates/                 # Go HTML templates (base, index, login, etc.)
-├── Dockerfile                 # Multi-stage: lint, build+test, then Alpine runtime
-├── Makefile                   # fmt, lint, test, check, build, docker targets
+│   ├── css/input.css          # Tailwind input, source for tailwind.css (make css)
+│   ├── css/tailwind.css       # Generated stylesheet the pages load
+│   ├── css/style.css          # Older hand-written stylesheet, no longer loaded
+│   ├── js/app.js              # Progressive-enhancement copy-to-clipboard
+│   ├── js/alpine.min.js       # Alpine.js, fetched by script/fetch-assets, not committed
+│   └── vendor.sha256          # Pinned hashes the fetched assets are verified against
+├── templates/                 # Go HTML templates (base, login, sources, etc.)
+├── script/                    # Scripts to Rule Them All entrypoints
+├── Dockerfile                 # Three stages: lint, test+build, Alpine runtime
+├── Dockerfile.lint            # Lint-only image built by script/lint
+├── Makefile                   # 10 of 16 targets shim script/; 6 are inline
 ├── go.mod / go.sum
 └── .golangci.yml              # Linter configuration
 ```
@@ -1098,21 +1202,27 @@ Components are wired via Uber fx in this order:
    user seed
 5. `database.NewWebhookDBManager` — Per-webhook event database
    lifecycle manager
-6. `healthcheck.New` — Health check service
-7. `session.New` — Cookie-based session manager (key from database)
-8. `handlers.New` — HTTP handlers
-9. `middleware.New` — HTTP middleware
-10. `delivery.New` — Event-driven delivery engine
-11. `delivery.Engine` → `handlers.DeliveryNotifier` — interface bridge
-12. `server.New` — HTTP server and router
+6. `database.NewRetentionReaper` — Per-webhook event retention sweep
+7. `healthcheck.New` — Health check service
+8. `session.New` — Cookie-based session manager (key from database)
+9. `handlers.New` — HTTP handlers
+10. `middleware.New` — HTTP middleware
+11. `delivery.New` — Event-driven delivery engine
+12. `delivery.NewArchiveSweeper` — Periodic pruning of idle archives
+13. `delivery.Engine` → `delivery.Notifier` — interface bridge
+14. `delivery.Engine` → `delivery.WebhookEvictor` — interface bridge so
+    deleting a webhook releases its archive writer
+15. `server.New` — HTTP server and router
 
-The server starts via `fx.Invoke(func(*server.Server, *delivery.Engine)
-{})` which triggers the fx lifecycle hooks in dependency order. The
-`DeliveryNotifier` interface allows the webhook handler to send
-self-contained `DeliveryTask` slices to the engine without a direct
+The server starts via `fx.Invoke(func(*server.Server, *delivery.Engine,
+*database.RetentionReaper, *delivery.ArchiveSweeper) {})`, which
+triggers the fx lifecycle hooks in dependency order. The
+`delivery.Notifier` interface allows the webhook handler to send
+self-contained `delivery.Task` slices to the engine without a direct
 package dependency. Each task carries all target config and event data
-inline (for bodies ≤16KB), so the engine can deliver without reading
-from any database — it only writes to record results.
+inline (for bodies under 16 KiB, `delivery.MaxInlineBodySize`), so the
+engine can deliver without reading from any database — it only writes
+to record results.
 
 ### Middleware Stack
 
@@ -1138,16 +1248,32 @@ CSRF middleware in every one of those route groups, because
 gorilla/csrf parses the form; if the cap were installed after it, form
 parsing would run under net/http's 10 MB default and the 1 MB limit
 would never apply. A request that declares a `Content-Length` over the
-limit is answered with `413 Request Entity Too Large` before any other
-middleware or handler runs; a chunked request, or one that lies about
-its length, is hard-capped by `http.MaxBytesReader` and fails
-downstream at form-parse time.
+limit is answered with `413 Request Entity Too Large` without its body
+being read and without reaching CSRF, the route group's remaining
+middleware, or the handler. It is not rejected before *any* other
+middleware, though: the global entries listed above all run first, so
+such a request is still logged and given the security headers — and
+counted in the metrics, on a deployment where `METRICS_USERNAME` is
+set and the Metrics middleware is therefore registered at all. The
+rejection itself is logged at `WARN` with the method, path and
+declared length. A chunked request, or
+one that lies about its length, is hard-capped by
+`http.MaxBytesReader` and fails downstream at form-parse time.
+
+Those same four route groups then apply **CSRF** and **NoCache**
+(`Cache-Control: no-store`, `Pragma: no-cache`), and every group except
+`/pages` applies **RequireAuth**. The rate limiters are per-route
+rather than global: **LoginRateLimit** on `/pages/login`,
+**PasswordChangeRateLimit** on `/user/{username}/password`, and
+**ReceiverRateLimit** on `/webhook/{uuid}`.
 
 ### Authentication
 
 - **Web UI:** Cookie-based sessions using gorilla/sessions with
   encrypted cookies. Sessions are configured with HttpOnly, SameSite
-  Lax, and Secure (in production). Session lifetime is 7 days.
+  Lax, and Secure (in production). Absolute session lifetime is 7 days,
+  with a sliding idle timeout on top of it (see
+  [Sessions](#sessions)).
 - **API (planned):** API key authentication via `Authorization: Bearer`
   header. API keys are stored per-user with usage tracking
   (`last_used_at`).
@@ -1179,33 +1305,79 @@ downstream at form-parse time.
   IPs before connecting, preventing DNS rebinding attacks)
 - **Login rate limiting** via [go-chi/httprate](https://github.com/go-chi/httprate):
   sliding-window rate limiter on the login endpoint, 5 POST attempts
-  per minute per bucket, to slow brute-force attacks. The bucket is per
-  client IP only when `TRUSTED_PROXIES` names the reverse proxy;
-  unset, every client shares one bucket and the login becomes remotely
-  deniable (see [Rate Limiting](#rate-limiting))
+  per minute per bucket, to slow brute-force attacks. GET requests to
+  the login page are not limited. The password-change endpoint carries
+  the same 5-per-minute limit. The bucket is per client IP only when
+  `TRUSTED_PROXIES` names the reverse proxy; unset, every client
+  shares one bucket and the login becomes remotely deniable (see
+  [Rate Limiting](#rate-limiting)). webhooker warns at startup
+  whenever `TRUSTED_PROXIES` is empty
 - Prometheus metrics behind basic auth
 - Static assets embedded in binary (no filesystem access needed at
   runtime)
 - Container runs as non-root user (UID 1000)
-- GORM soft deletes on all entities (data preserved for audit)
+- GORM soft deletes on every entity that carries `BaseModel`, which is
+  all of them but `Setting` (data preserved for audit)
+
+### Linting
+
+golangci-lint never runs on the host. `script/lint` builds
+`Dockerfile.lint`, which copies the repo into the digest-pinned
+golangci-lint image and lints as a build step, so a successful build is
+a clean lint. A host binary would share one cache and one lock with
+every other checkout on the machine, which has produced both invented
+findings attributed to other worktrees and unearned passes.
+
+Two properties are load-bearing:
+
+- `script/lint` passes `--no-cache-filter=lint`. Without it an unchanged
+  tree replays the lint layer from cache and the build exits 0 in under
+  a second having linted nothing. The `deps` stage stays cacheable, so
+  module downloads are not repeated. Invalidation is scoped to the one
+  stage; never prune the shared build cache.
+- Both lint steps use `RUN --network=none`. `golangci-lint config
+  verify` is documented as fetching its JSON schema over HTTPS, which
+  would be an unpinned remote dependency; the pinned image resolves the
+  schema without network access, and `--network=none` enforces that
+  instead of trusting it. Verify is worth keeping because
+  `golangci-lint run` silently ignores config keys it does not
+  recognize, so a typo would disable a setting with no warning.
 
 ### Docker
 
-The Dockerfile uses a multi-stage build:
+The Dockerfile uses a three-stage build. Each stage is pinned by
+digest, and the two check stages are separate images so the linter's
+version is fixed independently of the compiler's:
 
-1. **Builder stage** (Debian-based `golang:1.24`) — installs
-   golangci-lint, downloads dependencies, copies source, runs `make
-   check` (format verification, linting, tests, compilation).
-2. **Runtime stage** (`alpine:3.21`) — copies the binary, creates the
-   `/var/lib/webhooker` directory for all SQLite databases, runs as
-   non-root user, exposes port 8080, includes a health check.
+1. **Lint stage** (`golangci/golangci-lint:v2.12.2`, Debian-based) —
+   installs `make`, downloads dependencies, copies the source, and runs
+   `make fmt-check`, then `golangci-lint config verify` and
+   `golangci-lint run`, both with `--network=none`.
+2. **Builder stage** (`golang:1.26.1-bookworm`) — depends on the lint
+   stage passing (it copies a file from it), runs `script/fetch-assets`
+   to download and verify the third-party browser assets, then runs
+   `make test` and `make build`, and finally rebuilds the binary with
+   `CGO_ENABLED=1` and static linking so it runs on musl.
+3. **Runtime stage** (`alpine:3.21`) — copies the static binary,
+   creates the `/var/lib/webhooker` directory for all SQLite databases,
+   runs as the non-root `webhooker` user (UID 1000), exposes port 8080,
+   and includes a health check against `/.well-known/healthcheck`.
 
-The builder uses Debian rather than Alpine because GORM's SQLite
-dialect pulls in CGO-dependent headers at compile time. The runtime
-binary is statically linked and runs on Alpine.
+The lint stage invokes `golangci-lint` directly rather than `make lint`:
+it is already the pinned linter image, and `make lint` builds
+`Dockerfile.lint`, which would need a docker daemon inside this build.
 
-`docker build .` is the CI gate — if it passes, the code is formatted,
-linted, tested, and compiled.
+Both check stages use Debian rather than Alpine because
+`gorm.io/driver/sqlite` pulls in `mattn/go-sqlite3`, which needs CGO
+and does not compile against musl. Only the final binary is statically
+linked, which is what lets it run on the Alpine runtime image.
+
+`script/cibuild` — `docker build .` — is the CI gate: the four check
+targets run inside the image, so a build that succeeds is a repo that
+is formatted, linted, tested and compiled. `script/lint` also uses
+Docker (`Dockerfile.lint`, see Linting above), so `make lint` and
+`make check` run the same pinned linter version the gate does; only
+`script/test` and `script/fmt-check` run on the host.
 
 #### CI gate honesty
 
@@ -1218,19 +1390,20 @@ the hash of the last commit that touched the build context, so:
 - Any commit that changes code (including a squash merge whose tree
   matches an already-built branch) gets a new fingerprint, invalidates
   the `COPY . .` layer of both check stages, and really runs
-  `make fmt-check`, `make lint`, `make test`, and `make build`. A run
-  that reports success ran them.
+  `make fmt-check`, `golangci-lint`, `make test`, and `make build`. A
+  run that reports success ran them.
 - A docs-only commit leaves the fingerprint unchanged — `.dockerignore`
-  excludes `*.md` and `LICENSE` from the context anyway — so the image
-  replays from cache and costs seconds.
+  excludes `*.md`, `LICENSE` and `.editorconfig` from the context
+  anyway — so the image replays from cache and costs seconds.
 
 The module download layer sits above `COPY . .` and stays cached either
 way.
 
-The workflow's first step covers a second way the gate lied: Gitea
-cancels an in-flight run when a newer commit lands on the same branch
-and records that cancellation as a `failure` status, marking a commit
-red that was never tested. Cancellation is unconditional server-side for
+A separate workflow step, run before the fingerprint is written, covers
+a second way the gate lied: Gitea cancels an in-flight run when a newer
+commit lands on the same branch and records that cancellation as a
+`failure` status, marking a commit red that was never tested.
+Cancellation is unconditional server-side for
 push events, so the superseding run rewrites the exact
 `Has been cancelled` status to `skipped`. Genuine failures are never
 touched.

TODO.md

@@ -25,13 +25,17 @@ password change flow (#65), policy compliance (#6), pinned lint tooling
 (#55), and fail-loud configuration parsing (#80).
 
 `next` holds the completed 1.0.0 milestone: every issue in it is closed,
-and it is verified green both by CI and by cache-defeated container
-runs. The two were only made to mean the same thing this cycle — before
-#119, a warm layer cache let the gate report success without executing
-anything, and replayed the previous build's console log so the lie
-looked like a real run. Note: TODO.md was deliberately deleted from this
-repo in f9a9569 (2026-03-01, #6); its content was folded into the README
-TODO section, which this draft reconstructs as of 2026-07-06.
+and it is verified green by cache-defeated container runs
+(`docker build --no-cache-filter=lint --no-cache-filter=builder`). The
+CI status is not independently claimed here: a superseded run is
+recorded as `skipped` and still rolls up green, so a commit status on
+`next` does not by itself evidence an executed check (#152). Before
+#119, a warm layer cache also let the gate report success without
+executing anything, and replayed the previous build's console log so
+the lie looked like a real run. Note: `TODO.md` was deliberately
+deleted from this repo in f9a9569 (2026-03-01, #6); its content was
+folded into the README TODO section, which this draft reconstructs as
+of 2026-07-06.
 
 # Next Step
 
@@ -190,7 +194,9 @@ rate-limit keys should bucket by `/64`).
     - OpenAPI specification
 - Analytics dashboard: success rates, response times, volume
 - A remember-me option at login
-- Password change and reset flow
+- Password reset flow for a forgotten password. The authenticated
+  password *change* flow already landed on `main` (#65); reset does not
+  exist
 - Later, nice to have
     - email delivery target type
     - SNS and S3 delivery targets

internal/config/config.go

@@ -422,33 +422,43 @@ func loadFromEnv() (*Config, error) {
 	}, nil
 }
 
-// warnSharedRateLimitBucket logs a startup warning when a production
-// deployment leaves TRUSTED_PROXIES empty.
+// warnSharedRateLimitBucket logs a startup warning whenever
+// TRUSTED_PROXIES is empty, in any environment.
 //
 // With no trusted proxies every rate limiter keys on the connecting
-// peer's address. A production deployment is required to run behind a
-// TLS-terminating reverse proxy, and the peer is then that proxy for
-// every request, so all clients share one bucket per limiter. The
+// peer's address. Whether that is harmless or dangerous depends on
+// what is in front of the process, which this code cannot observe:
+// with nothing in front, the peer is the client and the limits are
+// per-client as intended; behind a reverse proxy the peer is the proxy
+// for every request, so all clients share one bucket per limiter. The
 // login limiter's bucket is the dangerous one: any remote client can
-// keep it full, which denies the only administrative login to
-// everyone until the process restarts.
+// keep it full, which denies the only administrative login to everyone
+// until the process restarts.
+//
+// The warning is deliberately not gated on WEBHOOKER_ENVIRONMENT. That
+// variable defaults to dev, so gating on it would silence the warning
+// for exactly the operator who forgot to configure the deployment —
+// the case it exists to catch.
 //
 // The default of trusting nobody is deliberate — trusting forwarded
 // headers from arbitrary peers lets any client choose its own bucket —
 // so this warns rather than failing startup or changing the key.
 func (c *Config) warnSharedRateLimitBucket(log *slog.Logger) {
-	if !c.IsProd() || len(c.TrustedProxies) > 0 {
+	if len(c.TrustedProxies) > 0 {
 		return
 	}
 
 	log.Warn(
-		"TRUSTED_PROXIES is empty: rate limits key on the "+
-			"connecting peer, so behind the reverse proxy a "+
-			"production deployment runs behind, every client "+
-			"shares one bucket per limit. Any remote client can "+
-			"then keep the login limit full and deny the admin "+
-			"login, the only administrative path, until restart. "+
-			"Set TRUSTED_PROXIES to your reverse proxy's address.",
+		"TRUSTED_PROXIES is empty: every rate limit keys on the "+
+			"connecting peer's address. With nothing proxying to "+
+			"this process that is the client itself and the limits "+
+			"are per-client as intended. Behind a reverse proxy the "+
+			"peer is the proxy on every request, so all clients "+
+			"share one bucket per limit and any remote client can "+
+			"keep the login limit full, denying the admin login — "+
+			"the only administrative path — until restart. If "+
+			"anything proxies to this process, set TRUSTED_PROXIES "+
+			"to its address.",
 		"environment", c.Environment,
 		"trustedProxies", len(c.TrustedProxies),
 	)
@@ -491,6 +501,10 @@ func New(lc fx.Lifecycle, params ConfigParams) (*Config, error) {
 		"maintenanceMode", s.MaintenanceMode,
 		"dataDir", s.DataDir,
 		"retentionSweepInterval", s.RetentionSweepInterval.String(),
+		// Logged because a perfectly valid non-positive value here
+		// disables idle expiry entirely, and that is worth showing
+		// back to the operator.
+		"sessionIdleTimeout", s.SessionIdleTimeout.String(),
 		"receiverRateLimit", s.ReceiverRateLimit,
 		"trustedProxies", len(s.TrustedProxies),
 		"hasSentryDSN", s.SentryDSN != "",

internal/config/config_test.go

@@ -628,10 +628,12 @@ func testTrustedProxiesSuccess(
 }
 
 // TestSharedRateLimitBucketWarning covers the startup warning that
-// tells an operator their production deployment shares one rate-limit
-// bucket between every client, which makes the admin login remotely
-// deniable. It must fire when TRUSTED_PROXIES is empty in production
-// and stay quiet otherwise.
+// tells an operator a deployment behind a reverse proxy shares one
+// rate-limit bucket between every client, which makes the admin login
+// remotely deniable. It must fire whenever TRUSTED_PROXIES is empty,
+// in any environment: WEBHOOKER_ENVIRONMENT defaults to dev, so gating
+// on it would silence the warning for exactly the operator who never
+// configured the deployment. It stays quiet once proxies are named.
 func TestSharedRateLimitBucketWarning(t *testing.T) {
 	tests := []struct {
 		name           string
@@ -651,12 +653,19 @@ func TestSharedRateLimitBucketWarning(t *testing.T) {
 			expectWarning:  false,
 		},
 		{
-			// Development is not required to run behind a
-			// reverse proxy, so the shared bucket the warning
-			// describes is not the expected shape there.
-			name:          "dev without trusted proxies is quiet",
+			// The default environment. An internet-exposed
+			// deployment whose operator never set
+			// WEBHOOKER_ENVIRONMENT lands here and has exactly
+			// the exposure the warning announces.
+			name:          "dev without trusted proxies warns",
 			environment:   config.EnvironmentDev,
-			expectWarning: false,
+			expectWarning: true,
+		},
+		{
+			name:           "dev with trusted proxies is quiet",
+			environment:    config.EnvironmentDev,
+			trustedProxies: cidrPrivateV4,
+			expectWarning:  false,
 		},
 	}
 
@@ -697,8 +706,14 @@ func TestSharedRateLimitBucketWarning(t *testing.T) {
 
 			assert.Contains(t, logged, `"level":"WARN"`)
 			assert.Contains(t, logged, "TRUSTED_PROXIES")
-			assert.Contains(t, logged, "shares one bucket")
-			assert.Contains(t, logged, "deny the admin login")
+			assert.Contains(t, logged, "share one bucket")
+			assert.Contains(t, logged, "denying the admin login")
+			// The text must stay accurate for a developer with
+			// nothing in front of the process, where an empty
+			// list costs nothing.
+			assert.Contains(
+				t, logged, "nothing proxying to this process",
+			)
 		})
 	}
 }

internal/middleware/ratelimit.go

@@ -48,6 +48,12 @@ const (
 	// bound every request pays a walk proportional to whatever the
 	// client sent.
 	maxForwardedHops = 64
+
+	// ipv6BucketBits is the prefix length IPv6 clients are bucketed
+	// on. A routed /64 is the normal residential and mobile
+	// allocation, so it is the unit an attacker gets addresses in
+	// and therefore the unit worth limiting.
+	ipv6BucketBits = 64
 )
 
 // normalizeAddr strips the IPv4-in-IPv6 wrapper and any zone from
@@ -56,6 +62,40 @@ func normalizeAddr(addr netip.Addr) netip.Addr {
 	return addr.Unmap().WithZone("")
 }
 
+// bucketKey is the rate-limit bucket identity of a client address.
+// IPv4 keys on the full address; IPv6 keys on its /64 prefix,
+// because keying IPv6 per /128 lets one ordinary subscriber rotate
+// source addresses inside its own routed /64 and mint a fresh bucket
+// per request — evading every limiter here at the network layer,
+// with no spoofing and nothing to detect.
+//
+// An IPv4-mapped address (::ffff:1.2.3.4) is keyed as the IPv4
+// address it carries, never masked to a /64: mapped form all shares
+// the ::ffff:0:0/96 prefix, so masking would collapse every IPv4
+// client reaching a proxy that emits it into one bucket. Callers
+// pass addresses through normalizeAddr, which already unmaps; the
+// unmap here keeps the property true of the key function itself.
+//
+// The two families cannot collide: an IPv4 key is a bare dotted
+// quad, and an IPv6 key always carries a "/64" suffix.
+func bucketKey(addr netip.Addr) string {
+	addr = addr.Unmap()
+
+	if addr.Is4() {
+		return addr.String()
+	}
+
+	// Prefix errors only on a negative bit count, on over 32 bits
+	// for an IPv4 address, or on over 128 for IPv6. The count here
+	// is the constant 64 and the IPv4 case returned above, so the
+	// error is unreachable. (The zero Addr does not error either: it
+	// yields the zero Prefix. Neither call site can produce one,
+	// since both parse the address first.)
+	prefix, _ := addr.Prefix(ipv6BucketBits)
+
+	return prefix.String()
+}
+
 // isTrustedProxy reports whether addr belongs to a network the
 // operator listed in TRUSTED_PROXIES. The list is empty by default,
 // so by default nothing is trusted.
@@ -143,6 +183,9 @@ func (m *Middleware) forwardedClientAddr(
 // another client's bucket, by picking an X-Forwarded-For value —
 // which makes every limit here decorative against a deliberate
 // attacker.
+//
+// The address that identifies the client is then reduced to a bucket
+// by bucketKey: full address for IPv4, /64 prefix for IPv6.
 func (m *Middleware) rateLimitKey(r *http.Request) (string, error) {
 	return m.clientKey(r), nil
 }
@@ -152,23 +195,25 @@ func (m *Middleware) clientKey(r *http.Request) string {
 	peer, err := netip.ParseAddr(ipFromHostPort(r.RemoteAddr))
 	if err != nil {
 		// Not an address we can reason about; key on the raw
-		// value, the most specific identity left. On a
-		// Unix-socket listener every peer carries the same
-		// RemoteAddr and so shares one bucket, which is the
-		// fail-closed direction.
+		// value, the most specific identity left. Distinct
+		// RemoteAddr values stay in distinct buckets, so this
+		// path cannot silently collapse unrelated clients
+		// together. On a Unix-socket listener every peer
+		// carries the same RemoteAddr and so shares one bucket,
+		// which is the fail-closed direction.
 		return r.RemoteAddr
 	}
 
 	peer = normalizeAddr(peer)
 	if !m.isTrustedProxy(peer) {
-		return peer.String()
+		return bucketKey(peer)
 	}
 
 	if addr, ok := m.forwardedClientAddr(r); ok {
-		return addr.String()
+		return bucketKey(addr)
 	}
 
-	return peer.String()
+	return bucketKey(peer)
 }
 
 // tooManyRequests returns the 429 handler used by the login,

internal/middleware/ratelimit_test.go

@@ -15,6 +15,7 @@ import (
 	"time"
 
 	"github.com/stretchr/testify/assert"
+	"github.com/stretchr/testify/require"
 	"sneak.berlin/go/webhooker/internal/config"
 	"sneak.berlin/go/webhooker/internal/middleware"
 )
@@ -370,6 +371,30 @@ const (
 	headerXFF  = "X-Forwarded-For"
 	headerReal = "X-Real-IP"
 	headerTrue = "True-Client-IP"
+
+	// clientIPv4 is the sample IPv4 client address these tests key
+	// on, both directly and in IPv4-mapped form. clientIPv4Alt is
+	// its neighbour, used to show the two do not share a bucket.
+	clientIPv4    = "198.51.100.7"
+	clientIPv4Alt = "198.51.100.8"
+
+	// clientIPv6 and clientIPv6Same are two addresses inside one
+	// routed /64, so both must key on clientBucketV6.
+	// clientIPv6Other is a different allocation and must key on
+	// clientOtherBucketV6.
+	clientIPv6          = "2001:db8:1:2:3:4:5:6"
+	clientIPv6Same      = "2001:db8:1:2:aaaa:bbbb:cccc:dddd"
+	clientIPv6Other     = "2001:db8:1:3::1"
+	clientBucketV6      = "2001:db8:1:2::/64"
+	clientOtherBucketV6 = "2001:db8:1:3::/64"
+
+	// trustedProxyCIDR is the proxy network the forwarded-path
+	// tests configure, and trustedPeer an address inside it. A
+	// production deployment is required to run behind a reverse
+	// proxy with TRUSTED_PROXIES set, so this is the shape the
+	// bucketing has to hold in.
+	trustedProxyCIDR = "10.0.0.0/8"
+	trustedPeer      = "10.0.0.1:44444"
 )
 
 // assertSharedBucket drives the login limiter from peer with the
@@ -458,8 +483,8 @@ func TestRateLimitKey_SingleValuedHeadersIgnoredFromTrustedPeer(
 			t.Parallel()
 
 			assertSharedBucket(
-				t, trustedProxies("10.0.0.0/8"),
-				"10.0.0.1:44444",
+				t, trustedProxies(trustedProxyCIDR),
+				trustedPeer,
 				func(i int) map[string]string {
 					return map[string]string{
 						header: fmt.Sprintf(
@@ -495,8 +520,8 @@ func TestRateLimitKey_MalformedRightmostHopFallsBackToPeer(
 			t.Parallel()
 
 			assertSharedBucket(
-				t, trustedProxies("10.0.0.0/8"),
-				"10.0.0.1:44444",
+				t, trustedProxies(trustedProxyCIDR),
+				trustedPeer,
 				func(i int) map[string]string {
 					return map[string]string{
 						headerXFF: fmt.Sprintf(
@@ -522,13 +547,13 @@ func TestRateLimitKey_ForwardedHonouredFromTrustedPeer(
 	t.Parallel()
 
 	m := rateLimitMiddleware(t, &config.Config{
-		TrustedProxies: trustedProxies("10.0.0.0/8"),
+		TrustedProxies: trustedProxies(trustedProxyCIDR),
 	})
 	handler := m.LoginRateLimit()(okHandler())
 
-	const peer = "10.0.0.1:44444"
+	const peer = trustedPeer
 
-	first := map[string]string{headerXFF: "198.51.100.7"}
+	first := map[string]string{headerXFF: clientIPv4}
 
 	for range middleware.LoginRateLimitConst {
 		postWithHeaders(handler, peer, loginPath, first)
@@ -542,7 +567,7 @@ func TestRateLimitKey_ForwardedHonouredFromTrustedPeer(
 
 	w = postWithHeaders(
 		handler, peer, loginPath,
-		map[string]string{headerXFF: "198.51.100.8"},
+		map[string]string{headerXFF: clientIPv4Alt},
 	)
 	assert.Equal(
 		t, http.StatusOK, w.Code,
@@ -559,7 +584,7 @@ func TestRateLimitKey_ChainWalkSkipsClientPrepended(t *testing.T) {
 	t.Parallel()
 
 	assertSharedBucket(
-		t, trustedProxies("10.0.0.0/8"), "10.0.0.1:44444",
+		t, trustedProxies(trustedProxyCIDR), trustedPeer,
 		func(i int) map[string]string {
 			return map[string]string{
 				headerXFF: fmt.Sprintf(
@@ -594,7 +619,7 @@ func TestRateLimitKey_LongChainCapsWalkAndFallsBackToPeer(
 	start := time.Now()
 
 	assertSharedBucket(
-		t, trustedProxies("10.0.0.0/8"), "10.0.0.1:44444",
+		t, trustedProxies(trustedProxyCIDR), trustedPeer,
 		func(i int) map[string]string {
 			return map[string]string{
 				headerXFF: fmt.Sprintf("9.9.9.%d%s", i+1, padding),
@@ -633,13 +658,13 @@ func TestRateLimitKey_LongChainAllocationIsBounded(t *testing.T) {
 	)
 
 	m := rateLimitMiddleware(t, &config.Config{
-		TrustedProxies: trustedProxies("10.0.0.0/8"),
+		TrustedProxies: trustedProxies(trustedProxyCIDR),
 	})
 
 	req := httptest.NewRequestWithContext(
 		context.Background(), http.MethodPost, loginPath, nil,
 	)
-	req.RemoteAddr = "10.0.0.1:44444"
+	req.RemoteAddr = trustedPeer
 	req.Header.Set(
 		headerXFF, "9.9.9.9"+strings.Repeat(", 10.0.0.2", hops),
 	)
@@ -835,3 +860,369 @@ func TestReceiverRateLimit_IgnoresForwardedFromUntrustedPeer(
 			"not mint a fresh receiver bucket",
 	)
 }
+
+// clientKeyFor returns the bucket key m computes for a request whose
+// direct peer is remoteAddr and which carries no forwarded headers.
+func clientKeyFor(
+	t *testing.T, m *middleware.Middleware, remoteAddr string,
+) string {
+	t.Helper()
+
+	req := httptest.NewRequestWithContext(
+		context.Background(), http.MethodPost, loginPath, nil,
+	)
+	req.RemoteAddr = remoteAddr
+
+	return middleware.ClientKeyForTest(m, req)
+}
+
+// TestRateLimitKey_IPv6BucketsByPrefix pins the key function's
+// address-family behaviour. IPv6 clients must bucket by /64 — a
+// routed /64 is the normal residential and mobile allocation, so
+// per-/128 keying lets one subscriber rotate source addresses and
+// mint a fresh bucket per request — while IPv4 keeps keying on the
+// full address and IPv4-mapped form is keyed as the IPv4 address it
+// carries.
+func TestRateLimitKey_IPv6BucketsByPrefix(t *testing.T) {
+	t.Parallel()
+
+	m := rateLimitMiddleware(t, &config.Config{})
+
+	for _, tc := range []struct {
+		name  string
+		peer  string
+		want  string
+		about string
+	}{{
+		name:  "ipv6",
+		peer:  "[" + clientIPv6 + "]:44444",
+		want:  clientBucketV6,
+		about: "an IPv6 peer must key on its /64",
+	}, {
+		name:  "ipv6-other-in-same-64",
+		peer:  "[" + clientIPv6Same + "]:1",
+		want:  clientBucketV6,
+		about: "another address in the same /64 must key the same",
+	}, {
+		name:  "ipv6-different-64",
+		peer:  "[" + clientIPv6Other + "]:44444",
+		want:  clientOtherBucketV6,
+		about: "a different /64 must key differently",
+	}, {
+		name:  "ipv4",
+		peer:  clientIPv4 + ":44444",
+		want:  clientIPv4,
+		about: "IPv4 must keep keying on the full address",
+	}, {
+		name:  "ipv4-neighbour",
+		peer:  clientIPv4Alt + ":44444",
+		want:  clientIPv4Alt,
+		about: "adjacent IPv4 addresses must not share a bucket",
+	}, {
+		name: "ipv4-mapped",
+		peer: "[::ffff:" + clientIPv4 + "]:44444",
+		want: clientIPv4,
+		about: "IPv4-mapped form must key as the IPv4 address, " +
+			"not be masked to a /64: mapped addresses all share " +
+			"::ffff:0:0/96, so masking would collapse every IPv4 " +
+			"client behind a mapping proxy into one bucket",
+	}} {
+		t.Run(tc.name, func(t *testing.T) {
+			t.Parallel()
+
+			assert.Equal(
+				t, tc.want, clientKeyFor(t, m, tc.peer), tc.about,
+			)
+		})
+	}
+}
+
+// TestRateLimitKey_FamiliesDoNotCollide pins the structure the
+// no-collision property rests on, rather than one sample pair: every
+// IPv4 key is a bare address and every IPv6 key is a /64 in CIDR
+// form, so the two name spaces are disjoint by shape. Dropping the
+// masking strips the suffix that guarantees it, which is why this
+// asserts the form of each key and not just that two of them differ.
+func TestRateLimitKey_FamiliesDoNotCollide(t *testing.T) {
+	t.Parallel()
+
+	// Restated here rather than imported from the package under
+	// test, so that changing the production bucket width fails this
+	// test instead of silently moving with it.
+	const wantBits = 64
+
+	m := rateLimitMiddleware(t, &config.Config{})
+
+	v4Keys := map[string]bool{}
+
+	for _, peer := range []string{
+		clientIPv4 + ":44444",
+		clientIPv4Alt + ":44444",
+		"[::ffff:" + clientIPv4 + "]:44444",
+	} {
+		key := clientKeyFor(t, m, peer)
+
+		addr, err := netip.ParseAddr(key)
+		require.NoError(
+			t, err, "%s: an IPv4 key must be a bare address", peer,
+		)
+		assert.True(
+			t, addr.Is4(),
+			"%s: an IPv4 key must be a dotted quad, got %q", peer, key,
+		)
+
+		v4Keys[key] = true
+	}
+
+	for _, peer := range []string{
+		"[" + clientIPv6 + "]:44444",
+		"[" + clientIPv6Same + "]:44444",
+		"[" + clientIPv6Other + "]:44444",
+		"[2001:db8::" + clientIPv4 + "]:44444",
+	} {
+		key := clientKeyFor(t, m, peer)
+
+		prefix, err := netip.ParsePrefix(key)
+		require.NoError(
+			t, err, "%s: an IPv6 key must be a CIDR prefix", peer,
+		)
+		assert.Equal(
+			t, wantBits, prefix.Bits(),
+			"%s: an IPv6 key must name a /64", peer,
+		)
+		assert.False(
+			t, v4Keys[key],
+			"%s: an IPv6 key must never equal an IPv4 key", peer,
+		)
+	}
+}
+
+// TestRateLimitKey_UnparseablePeerKeepsDistinctBuckets covers the
+// fallback path. A RemoteAddr that is not an address must not panic,
+// and must not drop unrelated clients into one shared bucket by
+// accident: the raw value is the most specific identity left, so
+// distinct values stay in distinct buckets.
+func TestRateLimitKey_UnparseablePeerKeepsDistinctBuckets(
+	t *testing.T,
+) {
+	t.Parallel()
+
+	m := rateLimitMiddleware(t, &config.Config{})
+
+	first := clientKeyFor(t, m, "not-an-address")
+	second := clientKeyFor(t, m, "also-not-an-address:1234")
+
+	assert.NotEmpty(t, first)
+	assert.NotEqual(
+		t, first, second,
+		"unparseable peers must not collapse into one bucket",
+	)
+}
+
+// TestLoginRateLimit_IPv6SharesBucketWithinSlash64 is the behavioural
+// half, and the regression test for the bypass itself: a client that
+// rotates source addresses inside its own routed /64 must stay in one
+// bucket. Reverting the masking makes this test fail, because each
+// rotated address would mint a fresh bucket and nothing would be
+// rejected.
+func TestLoginRateLimit_IPv6SharesBucketWithinSlash64(t *testing.T) {
+	t.Parallel()
+
+	m := rateLimitMiddleware(t, &config.Config{})
+	handler := m.LoginRateLimit()(okHandler())
+
+	for i := range middleware.LoginRateLimitConst {
+		w := postWithHeaders(
+			handler,
+			fmt.Sprintf("[2001:db8:1:2::%d]:44444", i+1),
+			loginPath, nil,
+		)
+		assert.Equal(
+			t, http.StatusOK, w.Code, "request %d should pass", i,
+		)
+	}
+
+	w := postWithHeaders(
+		handler, "[2001:db8:1:2::ffff]:44444", loginPath, nil,
+	)
+	assert.Equal(
+		t, http.StatusTooManyRequests, w.Code,
+		"rotating source addresses inside one routed /64 must not "+
+			"mint fresh buckets",
+	)
+}
+
+// TestLoginRateLimit_IPv6IndependentAcrossSlash64 is the other side
+// of the trade: bucketing by /64 must not merge separate allocations,
+// so a client in a different /64 keeps its own limit.
+func TestLoginRateLimit_IPv6IndependentAcrossSlash64(t *testing.T) {
+	t.Parallel()
+
+	m := rateLimitMiddleware(t, &config.Config{})
+	handler := m.LoginRateLimit()(okHandler())
+
+	for range middleware.LoginRateLimitConst + 1 {
+		postWithHeaders(
+			handler, "[2001:db8:1:2::1]:44444", loginPath, nil,
+		)
+	}
+
+	w := postWithHeaders(
+		handler, "[2001:db8:1:3::1]:44444", loginPath, nil,
+	)
+	assert.Equal(
+		t, http.StatusOK, w.Code,
+		"a different /64 must have its own bucket",
+	)
+}
+
+// TestLoginRateLimit_IPv4IndependentPerAddress guards against the
+// masking leaking into IPv4: two addresses one apart must still hold
+// separate buckets.
+func TestLoginRateLimit_IPv4IndependentPerAddress(t *testing.T) {
+	t.Parallel()
+
+	m := rateLimitMiddleware(t, &config.Config{})
+	handler := m.LoginRateLimit()(okHandler())
+
+	for range middleware.LoginRateLimitConst + 1 {
+		postWithHeaders(
+			handler, clientIPv4+":44444", loginPath, nil,
+		)
+	}
+
+	w := postWithHeaders(
+		handler, clientIPv4Alt+":44444", loginPath, nil,
+	)
+	assert.Equal(
+		t, http.StatusOK, w.Code,
+		"a second IPv4 address must have its own bucket",
+	)
+}
+
+// forwardedKeyFor returns the bucket key m computes for a request
+// that arrives from trustedPeer — a configured trusted proxy — and
+// names forwarded as its client in X-Forwarded-For. That is the
+// production path: a deployment is required to run behind a reverse
+// proxy with TRUSTED_PROXIES set, so the forwarded address, not the
+// peer, is what the limiters bucket on there.
+func forwardedKeyFor(
+	t *testing.T, m *middleware.Middleware, forwarded string,
+) string {
+	t.Helper()
+
+	req := httptest.NewRequestWithContext(
+		context.Background(), http.MethodPost, loginPath, nil,
+	)
+	req.RemoteAddr = trustedPeer
+	req.Header.Set(headerXFF, forwarded)
+
+	return middleware.ClientKeyForTest(m, req)
+}
+
+// TestRateLimitKey_ForwardedIPv6BucketsByPrefix pins the /64
+// bucketing on the trusted-proxy branch. The direct-peer tests above
+// cannot reach it, so without this the masking could be reverted for
+// forwarded clients alone — the only shape a production deployment
+// runs in — and the rest of the suite would stay green.
+func TestRateLimitKey_ForwardedIPv6BucketsByPrefix(t *testing.T) {
+	t.Parallel()
+
+	m := rateLimitMiddleware(t, &config.Config{
+		TrustedProxies: trustedProxies(trustedProxyCIDR),
+	})
+
+	for _, tc := range []struct {
+		name      string
+		forwarded string
+		want      string
+		about     string
+	}{{
+		name:      "ipv6",
+		forwarded: clientIPv6,
+		want:      clientBucketV6,
+		about:     "a forwarded IPv6 client must key on its /64",
+	}, {
+		name:      "ipv6-other-in-same-64",
+		forwarded: clientIPv6Same,
+		want:      clientBucketV6,
+		about: "another forwarded address in the same /64 must " +
+			"key the same",
+	}, {
+		name:      "ipv6-different-64",
+		forwarded: clientIPv6Other,
+		want:      clientOtherBucketV6,
+		about:     "a forwarded address in another /64 must differ",
+	}, {
+		name:      "ipv4",
+		forwarded: clientIPv4,
+		want:      clientIPv4,
+		about:     "a forwarded IPv4 client must key on the address",
+	}, {
+		name:      "ipv4-mapped",
+		forwarded: "::ffff:" + clientIPv4,
+		want:      clientIPv4,
+		about: "a proxy that forwards IPv4-mapped form must key as " +
+			"the IPv4 address it carries, not be masked to a /64: " +
+			"mapped addresses all share ::ffff:0:0/96",
+	}} {
+		t.Run(tc.name, func(t *testing.T) {
+			t.Parallel()
+
+			assert.Equal(
+				t, tc.want,
+				forwardedKeyFor(t, m, tc.forwarded), tc.about,
+			)
+		})
+	}
+}
+
+// TestLoginRateLimit_ForwardedIPv6SharesBucketWithinSlash64 is the
+// behavioural half on the production path: behind a trusted proxy, a
+// client rotating source addresses inside its own routed /64 must
+// stay in one bucket.
+func TestLoginRateLimit_ForwardedIPv6SharesBucketWithinSlash64(
+	t *testing.T,
+) {
+	t.Parallel()
+
+	assertSharedBucket(
+		t, trustedProxies(trustedProxyCIDR), trustedPeer,
+		func(i int) map[string]string {
+			return map[string]string{
+				headerXFF: fmt.Sprintf("2001:db8:1:2::%d", i+1),
+			}
+		},
+		"rotating forwarded source addresses inside one routed /64 "+
+			"must not mint fresh buckets",
+	)
+}
+
+// TestLoginRateLimit_ForwardedIPv6IndependentAcrossSlash64 is the
+// other side of that trade on the same path: bucketing by /64 must
+// not merge two allocations reaching the proxy.
+func TestLoginRateLimit_ForwardedIPv6IndependentAcrossSlash64(
+	t *testing.T,
+) {
+	t.Parallel()
+
+	m := rateLimitMiddleware(t, &config.Config{
+		TrustedProxies: trustedProxies(trustedProxyCIDR),
+	})
+	handler := m.LoginRateLimit()(okHandler())
+
+	spent := map[string]string{headerXFF: clientIPv6}
+	for range middleware.LoginRateLimitConst + 1 {
+		postWithHeaders(handler, trustedPeer, loginPath, spent)
+	}
+
+	w := postWithHeaders(
+		handler, trustedPeer, loginPath,
+		map[string]string{headerXFF: clientIPv6Other},
+	)
+	assert.Equal(
+		t, http.StatusOK, w.Code,
+		"a forwarded client in a different /64 must have its own "+
+			"bucket",
+	)
+}

internal/server/routes_test.go

@@ -24,6 +24,7 @@ import (
 	"sneak.berlin/go/webhooker/internal/middleware"
 	"sneak.berlin/go/webhooker/internal/server"
 	"sneak.berlin/go/webhooker/internal/session"
+	"sneak.berlin/go/webhooker/static"
 )
 
 // csrfCookieName is the cookie gorilla/csrf issues when it runs. Its
@@ -246,6 +247,56 @@ func (e *testEnv) storedHash(t *testing.T, username string) string {
 	return user.Password
 }
 
+// --- /s static group ---
+
+// TestStaticServesEveryMethod pins what the static mount actually
+// answers. chi's Mount registers the handler for all methods and
+// http.FileServer only special-cases HEAD (by suppressing the body),
+// so a POST or a DELETE to an asset is served the file rather than
+// refused. The README documents this; the test is what keeps the two
+// from drifting.
+func TestStaticServesEveryMethod(t *testing.T) {
+	t.Parallel()
+
+	env := newTestEnv(t)
+
+	body, err := static.Static.ReadFile("js/app.js")
+	require.NoError(t, err)
+	require.NotEmpty(t, body)
+
+	for _, method := range []string{
+		http.MethodGet,
+		http.MethodHead,
+		http.MethodPost,
+		http.MethodPut,
+		http.MethodDelete,
+	} {
+		t.Run(method, func(t *testing.T) {
+			t.Parallel()
+
+			req := httptest.NewRequestWithContext(
+				context.Background(), method,
+				"/s/js/app.js", nil,
+			)
+			w := httptest.NewRecorder()
+			env.router.ServeHTTP(w, req)
+
+			assert.Equal(t, http.StatusOK, w.Code,
+				"static mount answers every method")
+
+			if method == http.MethodHead {
+				assert.Empty(t, w.Body.Bytes(),
+					"HEAD must not carry a body")
+
+				return
+			}
+
+			assert.Equal(t, body, w.Body.Bytes(),
+				"the asset itself is returned")
+		})
+	}
+}
+
 // --- /pages group ---
 
 // TestPagesLogin_OversizeBody_RejectedBeforeCSRF proves the cap runs

script/bootstrap

@@ -3,20 +3,14 @@
 # this repo. Idempotent: every install is guarded by a check so already
 # installed tools are skipped. Base tooling comes from nix, apt, brew,
 # or apk (detected in that order); assumes NOTHING is present (not git,
-# make, or go). golangci-lint is packaged in nix, brew, and apk; on apt
-# it is installed from a hash-verified GitHub release archive (never
-# curl | sh). Finishes by running script/fetch-assets, which installs the
-# hash-pinned third-party browser assets the repo does not commit.
+# make, or go). golangci-lint is deliberately not installed: linting runs
+# only in docker, via script/lint and Dockerfile.lint. Finishes by running
+# script/fetch-assets, which installs the hash-pinned third-party browser
+# assets the repo does not commit.
 set -eu
 
 ROOT="$(cd "$(dirname "$0")/.." && pwd -P)"
 
-# Pinned versions, 2026-08-07. Never "latest"; exact versions only.
-GOLANGCI_LINT_VERSION="2.12.2"
-# sha256 of golangci-lint-2.12.2-linux-<arch>.tar.gz release archives
-GOLANGCI_LINT_SHA256_AMD64="8df580d2670fed8fa984aac0507099af8df275e665215f5c7a2ae3943893a553"
-GOLANGCI_LINT_SHA256_ARM64="44cd40a8c76c86755375adfeea52cfd3533cb43d7bd647771e0ae065e166df3a"
-
 PKGMGR=""
 SUDO=""
 
@@ -57,52 +51,6 @@ missing() {
     ! command -v "$1" >/dev/null 2>&1
 }
 
-# verify_sha256 <file> <expected-hash>
-verify_sha256() {
-    if command -v sha256sum >/dev/null 2>&1; then
-        actual="$(sha256sum "$1" | cut -d' ' -f1)"
-    else
-        actual="$(shasum -a 256 "$1" | cut -d' ' -f1)"
-    fi
-    if [ "$actual" != "$2" ]; then
-        echo "bootstrap: sha256 mismatch for $1" >&2
-        echo "  expected: $2" >&2
-        echo "  actual:   $actual" >&2
-        exit 1
-    fi
-}
-
-# apt has no golangci-lint package: install a pinned release archive
-# from GitHub, verified by hardcoded sha256 (never curl | sh).
-install_golangci_lint_release() {
-    case "$(uname -m)" in
-        x86_64) goarch="amd64"; sha="$GOLANGCI_LINT_SHA256_AMD64" ;;
-        aarch64|arm64) goarch="arm64"; sha="$GOLANGCI_LINT_SHA256_ARM64" ;;
-        *)
-            echo "bootstrap: unsupported architecture $(uname -m)" >&2
-            exit 1
-            ;;
-    esac
-    if missing curl; then pkg_install curl curl curl curl; fi
-    name="golangci-lint-${GOLANGCI_LINT_VERSION}-linux-${goarch}"
-    tmp="$(mktemp -d)"
-    curl -fsSL -o "$tmp/$name.tar.gz" \
-        "https://github.com/golangci/golangci-lint/releases/download/v${GOLANGCI_LINT_VERSION}/${name}.tar.gz"
-    verify_sha256 "$tmp/$name.tar.gz" "$sha"
-    tar -xzf "$tmp/$name.tar.gz" -C "$tmp"
-    $SUDO install -m 0755 "$tmp/$name/golangci-lint" /usr/local/bin/golangci-lint
-    rm -rf "$tmp"
-}
-
-ensure_golangci_lint() {
-    if ! missing golangci-lint; then return 0; fi
-    detect_pkgmgr
-    case "$PKGMGR" in
-        apt) install_golangci_lint_release ;;
-        *) pkg_install golangci-lint golangci-lint golangci-lint golangci-lint ;;
-    esac
-}
-
 main() {
     cd "$ROOT"
 
@@ -110,9 +58,14 @@ main() {
     if missing git; then pkg_install git git git git; fi
     if missing make; then pkg_install gnumake make make make; fi
 
-    # Go toolchain and linter
+    # Go toolchain
     if missing go; then pkg_install go golang go go; fi
-    ensure_golangci_lint
+
+    # Not installed here: docker is platform-specific and out of scope for a
+    # package-manager bootstrap, but script/lint needs it.
+    if missing docker; then
+        echo "bootstrap: docker not found; script/lint requires it" >&2
+    fi
 
     go mod download
 

script/lint

@@ -1,12 +1,55 @@
 #!/bin/sh
-# script/lint: run the linter.
+# script/lint: run the linter. golangci-lint is never installed locally: it
+# runs via docker only, one way, everywhere — script/lint builds
+# Dockerfile.lint, which COPYs the repo into the pinned golangci-lint image
+# and lints as a build step. This works even when the docker daemon is remote
+# and bind mounts are impossible, and it removes the host linter's shared
+# cache, which has attributed other checkouts' findings to this one.
+#
+# --no-cache-filter=lint forces the lint stage to re-execute on every run; a
+# cached lint stage exits 0 in under a second having linted nothing. The deps
+# stage keeps its cache, so module downloads are not repeated.
+# --progress=plain keeps the linter's own output visible on success, so a
+# passing run shows the issue count rather than nothing.
+# --output=type=cacheonly leaves no image behind to clean up.
+#
+# docker silently ignores --no-cache-filter for a stage name that does not
+# match, so a rename or a typo would restore the cached false green with no
+# warning and a fast exit 0. The flag is therefore not trusted: the build
+# output is teed to a log and a run is only a pass if golangci-lint's own
+# summary line ("N issues." / "N issues:") is in it. No summary, no lint,
+# whatever the exit code says.
 set -eu
 
 ROOT="$(cd "$(dirname "$0")/.." && pwd -P)"
 
 main() {
     cd "$ROOT"
-    golangci-lint run --config .golangci.yml ./...
+
+    log="$(mktemp -t webhooker-lint.XXXXXXXX)"
+    rcfile="$(mktemp -t webhooker-lint-rc.XXXXXXXX)"
+    trap 'rm -f "$log" "$rcfile"' EXIT INT TERM
+
+    # The pipeline's status is tee's, and POSIX sh has no pipefail, so the
+    # build's status travels via a file. Output still streams live.
+    {
+        docker build \
+            -f Dockerfile.lint \
+            --no-cache-filter=lint \
+            --progress=plain \
+            --output=type=cacheonly \
+            . 2>&1 && echo 0 >"$rcfile" || echo $? >"$rcfile"
+    } | tee "$log" >&2
+
+    rc="$(cat "$rcfile")"
+    [ "$rc" -eq 0 ] || exit "$rc"
+
+    if ! grep -qE '[0-9]+ issues[.:]' "$log"; then
+        echo "script/lint: golangci-lint printed no summary line; the linter" >&2
+        echo "  did not run. Check that the stage named in --no-cache-filter" >&2
+        echo "  still matches a stage in Dockerfile.lint." >&2
+        exit 1
+    fi
 }
 
 main "$@"