diff --git a/.prettierignore b/.prettierignore
index d87c685..c9cb794 100644
--- a/.prettierignore
+++ b/.prettierignore
@@ -1,2 +1,5 @@
+node_modules/
+yarn.lock
+
 # Vendored, minified third-party bundles must never be reformatted.
 *.min.js
diff --git a/.prettierrc b/.prettierrc
new file mode 100644
index 0000000..8af31cd
--- /dev/null
+++ b/.prettierrc
@@ -0,0 +1,4 @@
+{
+    "tabWidth": 4,
+    "proseWrap": "always"
+}
diff --git a/CONVENTIONS.md b/CONVENTIONS.md
index 6f7c217..53bc824 100644
--- a/CONVENTIONS.md
+++ b/CONVENTIONS.md
@@ -1,6 +1,8 @@
 # Go HTTP Server Conventions
 
-This document defines the architectural patterns, design decisions, and conventions for building Go HTTP servers. All new projects must follow these standards.
+This document defines the architectural patterns, design decisions, and
+conventions for building Go HTTP servers. All new projects must follow these
+standards.
 
 ## Table of Contents
 
@@ -25,18 +27,18 @@ This document defines the architectural patterns, design decisions, and conventi
 
 These libraries are **mandatory** for all new projects:
 
-| Purpose | Library | Import Path |
-|---------|---------|-------------|
-| Dependency Injection | Uber fx | `go.uber.org/fx` |
-| HTTP Router | go-chi | `github.com/go-chi/chi` |
-| Logging | slog (stdlib) | `log/slog` |
-| Configuration | Viper | `github.com/spf13/viper` |
-| Environment Loading | godotenv | `github.com/joho/godotenv/autoload` |
-| CORS | go-chi/cors | `github.com/go-chi/cors` |
-| Error Reporting | Sentry | `github.com/getsentry/sentry-go` |
-| Metrics | Prometheus | `github.com/prometheus/client_golang` |
-| Metrics Middleware | go-http-metrics | `github.com/slok/go-http-metrics` |
-| Basic Auth | basicauth-go | `github.com/99designs/basicauth-go` |
+| Purpose              | Library         | Import Path                           |
+| -------------------- | --------------- | ------------------------------------- |
+| Dependency Injection | Uber fx         | `go.uber.org/fx`                      |
+| HTTP Router          | go-chi          | `github.com/go-chi/chi`               |
+| Logging              | slog (stdlib)   | `log/slog`                            |
+| Configuration        | Viper           | `github.com/spf13/viper`              |
+| Environment Loading  | godotenv        | `github.com/joho/godotenv/autoload`   |
+| CORS                 | go-chi/cors     | `github.com/go-chi/cors`              |
+| Error Reporting      | Sentry          | `github.com/getsentry/sentry-go`      |
+| Metrics              | Prometheus      | `github.com/prometheus/client_golang` |
+| Metrics Middleware   | go-http-metrics | `github.com/slok/go-http-metrics`     |
+| Basic Auth           | basicauth-go    | `github.com/99designs/basicauth-go`   |
 
 ---
 
@@ -85,7 +87,8 @@ project-root/
 ### Key Principles
 
 - **`cmd/{appname}/`**: Only the entry point. Minimal logic, just bootstrapping.
-- **`internal/`**: All application packages. Not importable by external projects.
+- **`internal/`**: All application packages. Not importable by external
+  projects.
 - **One package per concern**: config, database, handlers, middleware, etc.
 - **Flat handler files**: One file per handler or logical group of handlers.
 
@@ -190,7 +193,8 @@ Providers are resolved automatically by fx, but conceptually follow this order:
 2. `logger.New` - Logger (depends on Globals)
 3. `config.New` - Configuration (depends on Globals, Logger)
 4. `database.New` - Database (depends on Logger, Config)
-5. `healthcheck.New` - Health check (depends on Globals, Config, Logger, Database)
+5. `healthcheck.New` - Health check (depends on Globals, Config, Logger,
+   Database)
 6. `middleware.New` - Middleware (depends on Logger, Globals, Config)
 7. `handlers.New` - Handlers (depends on Logger, Globals, Database, Healthcheck)
 8. `server.New` - Server (depends on all above)
@@ -453,7 +457,8 @@ func New(lc fx.Lifecycle, params HandlersParams) (*Handlers, error) {
 
 ### Closure-Based Handler Pattern
 
-All handlers return `http.HandlerFunc` using the closure pattern. This allows initialization logic to run once when the handler is created:
+All handlers return `http.HandlerFunc` using the closure pattern. This allows
+initialization logic to run once when the handler is created:
 
 ```go
 // internal/handlers/index.go
@@ -510,7 +515,8 @@ func (s *Handlers) decodeJSON(w http.ResponseWriter, r *http.Request, v interfac
 ### Handler Naming Convention
 
 - `HandleIndex()` - Main page
-- `HandleLoginGET()` / `HandleLoginPOST()` - Form handlers with HTTP method suffix
+- `HandleLoginGET()` / `HandleLoginPOST()` - Form handlers with HTTP method
+  suffix
 - `HandleNow()` - API endpoints
 - `HandleHealthCheck()` - System endpoints
 
@@ -733,7 +739,8 @@ func New(lc fx.Lifecycle, params ConfigParams) (*Config, error) {
 
 1. **Environment variables** (highest priority via `AutomaticEnv()`)
 2. **`.env` file** (loaded via `godotenv/autoload` import)
-3. **Config files**: `/etc/{appname}/{appname}.yaml`, `~/.config/{appname}/{appname}.yaml`
+3. **Config files**: `/etc/{appname}/{appname}.yaml`,
+   `~/.config/{appname}/{appname}.yaml`
 4. **Defaults** (lowest priority)
 
 ### Environment Loading
@@ -1005,6 +1012,7 @@ var Static embed.FS
 ```
 
 Directory structure:
+
 ```
 static/
 ├── static.go
@@ -1045,15 +1053,13 @@ Templates use Go's template composition:
 
 ```html
 <!-- index.html -->
-{{ template "htmlheader.html" . }}
-{{ template "navbar.html" . }}
+{{ template "htmlheader.html" . }} {{ template "navbar.html" . }}
 
 <main>
     <!-- Page content -->
 </main>
 
-{{ template "pagefooter.html" . }}
-{{ template "htmlfooter.html" . }}
+{{ template "pagefooter.html" . }} {{ template "htmlfooter.html" . }}
 ```
 
 ### Static Asset References
@@ -1214,12 +1220,12 @@ if viper.GetString("METRICS_USERNAME") != "" {
 
 ### Environment Variables Summary
 
-| Variable | Description | Default |
-|----------|-------------|---------|
-| `PORT` | HTTP listen port | 8080 |
-| `DEBUG` | Enable debug logging | false |
-| `DBURL` | Database connection URL | "" |
-| `SENTRY_DSN` | Sentry DSN for error reporting | "" |
-| `MAINTENANCE_MODE` | Enable maintenance mode | false |
-| `METRICS_USERNAME` | Basic auth username for /metrics | "" |
-| `METRICS_PASSWORD` | Basic auth password for /metrics | "" |
+| Variable           | Description                      | Default |
+| ------------------ | -------------------------------- | ------- |
+| `PORT`             | HTTP listen port                 | 8080    |
+| `DEBUG`            | Enable debug logging             | false   |
+| `DBURL`            | Database connection URL          | ""      |
+| `SENTRY_DSN`       | Sentry DSN for error reporting   | ""      |
+| `MAINTENANCE_MODE` | Enable maintenance mode          | false   |
+| `METRICS_USERNAME` | Basic auth username for /metrics | ""      |
+| `METRICS_PASSWORD` | Basic auth password for /metrics | ""      |
diff --git a/README.md b/README.md
index 09ea48f..a7488e3 100644
--- a/README.md
+++ b/README.md
@@ -1,12 +1,14 @@
 # µPaaS by [@sneak](https://sneak.berlin)
 
-A simple self-hosted PaaS that auto-deploys Docker containers from Git repositories via webhooks from Gitea, GitHub, or GitLab.
+A simple self-hosted PaaS that auto-deploys Docker containers from Git
+repositories via webhooks from Gitea, GitHub, or GitLab.
 
 ## Features
 
 - Single admin user with argon2id password hashing
 - Per-app SSH keypairs for read-only deploy keys
-- Per-app UUID-based webhook URLs with auto-detection of Gitea, GitHub, and GitLab
+- Per-app UUID-based webhook URLs with auto-detection of Gitea, GitHub, and
+  GitLab
 - Branch filtering - only deploy on configured branch changes
 - Environment variables, labels, and volume mounts per app
 - CPU and memory resource limits per app
@@ -95,9 +97,12 @@ chi Router ──► Middleware Stack ──► Handler
 
 ### Key Patterns
 
-- **Closure-based handlers**: Handlers return `http.HandlerFunc` allowing one-time initialization
-- **Active Record models**: Models encapsulate database operations (`Save()`, `Delete()`, `Reload()`)
-- **Async deployments**: Webhook triggers deploy via goroutine with `context.WithoutCancel()`
+- **Closure-based handlers**: Handlers return `http.HandlerFunc` allowing
+  one-time initialization
+- **Active Record models**: Models encapsulate database operations (`Save()`,
+  `Delete()`, `Reload()`)
+- **Async deployments**: Webhook triggers deploy via goroutine with
+  `context.WithoutCancel()`
 - **Embedded assets**: Templates and static files embedded via `//go:embed`
 
 ## Entrypoints
@@ -105,12 +110,12 @@ chi Router ──► Middleware Stack ──► Handler
 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, and the Makefile targets are thin shims that call them. We
+provide:
 
 - `script/bootstrap` — install all dependencies (idempotent)
-- `script/setup` — make a fresh clone ready for development
-  (bootstrap, then install-precommit)
+- `script/setup` — make a fresh clone ready for development (bootstrap, then
+  install-precommit)
 - `script/projectname` — output the project name ("upaas")
 - `script/test` — run the test suite
 - `script/lint` — run golangci-lint
@@ -118,12 +123,12 @@ them. We provide:
 - `script/fmt-check` — check formatting (read-only)
 - `script/check` — run test, lint, and fmt-check
 - `script/docker` — build the Docker image tagged via `script/projectname`
-- `script/cibuild` — CI entrypoint: `docker build .` (the Dockerfile
-  runs the checks, so a green build implies a green repo)
+- `script/cibuild` — CI entrypoint: `docker build .` (the Dockerfile runs the
+  checks, so a green build implies a green repo)
 - `script/precommit` — pre-commit checks (`go mod tidy` guard, then
   `script/check`)
-- `script/install-precommit` — install the git pre-commit hook that
-  runs `script/precommit`
+- `script/install-precommit` — install the git pre-commit hook that runs
+  `script/precommit`
 
 ## Development
 
@@ -156,11 +161,11 @@ Before every commit:
 
 1. **Format**: Run `make fmt` to format all code
 2. **Lint**: Run `make lint` and fix all errors/warnings
-   - Do not disable linters or add nolint comments without good reason
-   - Fix the code, don't hide the problem
+    - Do not disable linters or add nolint comments without good reason
+    - Fix the code, don't hide the problem
 3. **Test**: Run `make test` and ensure all tests pass
-   - Fix failing tests by fixing the code, not by modifying tests to pass
-   - Add tests for new functionality
+    - Fix failing tests by fixing the code, not by modifying tests to pass
+    - Add tests for new functionality
 4. **Verify**: Run `make check` to confirm everything passes
 
 ```bash
@@ -174,6 +179,7 @@ git commit -m "Your message"
 ```
 
 The Docker build runs `make check` and will fail if:
+
 - Code is not formatted
 - Linting errors exist
 - Tests fail
@@ -185,17 +191,17 @@ This ensures the main branch always contains clean, tested, working code.
 
 Environment variables:
 
-| Variable | Description | Default |
-|----------|-------------|---------|
-| `PORT` | HTTP listen port | 8080 |
-| `UPAAS_DATA_DIR` | Data directory for SQLite and keys | `./data` (local dev only — use absolute path for Docker) |
-| `UPAAS_HOST_DATA_DIR` | Host path for DATA_DIR (when running in container) | *(none — must be set to an absolute path)* |
-| `UPAAS_DOCKER_HOST` | Docker socket path | unix:///var/run/docker.sock |
-| `UPAAS_PLAINTEXT_HTTP` | Set when µPaaS is reached over plain HTTP (no TLS-terminating proxy in front) so CSRF origin checks use `http://`. Leave unset behind a TLS-terminating reverse proxy. | false |
-| `DEBUG` | Enable debug logging | false |
-| `SENTRY_DSN` | Sentry error reporting DSN | "" |
-| `METRICS_USERNAME` | Basic auth for /metrics | "" |
-| `METRICS_PASSWORD` | Basic auth for /metrics | "" |
+| Variable               | Description                                                                                                                                                            | Default                                                  |
+| ---------------------- | ---------------------------------------------------------------------------------------------------------------------------------------------------------------------- | -------------------------------------------------------- |
+| `PORT`                 | HTTP listen port                                                                                                                                                       | 8080                                                     |
+| `UPAAS_DATA_DIR`       | Data directory for SQLite and keys                                                                                                                                     | `./data` (local dev only — use absolute path for Docker) |
+| `UPAAS_HOST_DATA_DIR`  | Host path for DATA_DIR (when running in container)                                                                                                                     | _(none — must be set to an absolute path)_               |
+| `UPAAS_DOCKER_HOST`    | Docker socket path                                                                                                                                                     | unix:///var/run/docker.sock                              |
+| `UPAAS_PLAINTEXT_HTTP` | Set when µPaaS is reached over plain HTTP (no TLS-terminating proxy in front) so CSRF origin checks use `http://`. Leave unset behind a TLS-terminating reverse proxy. | false                                                    |
+| `DEBUG`                | Enable debug logging                                                                                                                                                   | false                                                    |
+| `SENTRY_DSN`           | Sentry error reporting DSN                                                                                                                                             | ""                                                       |
+| `METRICS_USERNAME`     | Basic auth for /metrics                                                                                                                                                | ""                                                       |
+| `METRICS_PASSWORD`     | Basic auth for /metrics                                                                                                                                                | ""                                                       |
 
 ## Running with Docker
 
@@ -217,35 +223,38 @@ TLS-terminating reverse proxy, drop that line.
 
 ```yaml
 services:
-  upaas:
-    build: .
-    restart: unless-stopped
-    ports:
-      - "8080:8080"
-    volumes:
-      - /var/run/docker.sock:/var/run/docker.sock
-      - ${HOST_DATA_DIR}:/var/lib/upaas
-    environment:
-      - UPAAS_HOST_DATA_DIR=${HOST_DATA_DIR}
-      # Set when serving plain HTTP (no TLS-terminating proxy); drop behind one
-      - UPAAS_PLAINTEXT_HTTP=true
-      # Optional: uncomment to enable debug logging
-      # - DEBUG=true
-      # Optional: Sentry error reporting
-      # - SENTRY_DSN=https://...
-      # Optional: Prometheus metrics auth
-      # - METRICS_USERNAME=prometheus
-      # - METRICS_PASSWORD=secret
+    upaas:
+        build: .
+        restart: unless-stopped
+        ports:
+            - "8080:8080"
+        volumes:
+            - /var/run/docker.sock:/var/run/docker.sock
+            - ${HOST_DATA_DIR}:/var/lib/upaas
+        environment:
+            - UPAAS_HOST_DATA_DIR=${HOST_DATA_DIR}
+            # Set when serving plain HTTP (no TLS-terminating proxy); drop behind one
+            - UPAAS_PLAINTEXT_HTTP=true
+            # Optional: uncomment to enable debug logging
+            # - DEBUG=true
+            # Optional: Sentry error reporting
+            # - SENTRY_DSN=https://...
+            # Optional: Prometheus metrics auth
+            # - METRICS_USERNAME=prometheus
+            # - METRICS_PASSWORD=secret
 ```
 
-**Important**: You **must** set `HOST_DATA_DIR` to an **absolute path** on the host before running
-`docker compose up`. This value is bind-mounted into the container and passed as `UPAAS_HOST_DATA_DIR`
-so that Docker bind mounts during builds resolve correctly. Relative paths (e.g. `./data`) will break
-container builds because the Docker daemon resolves paths relative to the host, not the container.
+**Important**: You **must** set `HOST_DATA_DIR` to an **absolute path** on the
+host before running `docker compose up`. This value is bind-mounted into the
+container and passed as `UPAAS_HOST_DATA_DIR` so that Docker bind mounts during
+builds resolve correctly. Relative paths (e.g. `./data`) will break container
+builds because the Docker daemon resolves paths relative to the host, not the
+container.
 
 Example: `HOST_DATA_DIR=/srv/upaas/data docker compose up -d`
 
-Session secrets are automatically generated on first startup and persisted to `$UPAAS_DATA_DIR/session.key`.
+Session secrets are automatically generated on first startup and persisted to
+`$UPAAS_DATA_DIR/session.key`.
 
 ## License
 
diff --git a/TODO.md b/TODO.md
index ae65dff..bf456fe 100644
--- a/TODO.md
+++ b/TODO.md
@@ -1,70 +1,75 @@
 # Workflow
 
-* branch (from `main`)
-* do the work in Next Step
-* move Next Step to the top of Completed Steps
-* move the top item of Future Steps into Next Step
-* commit (`TODO.md` changes in the same commit as the work)
-* merge to `main` if the branch is not protected, otherwise open a PR
-* push
+- branch (from `main`)
+- do the work in Next Step
+- move Next Step to the top of Completed Steps
+- move the top item of Future Steps into Next Step
+- commit (`TODO.md` changes in the same commit as the work)
+- merge to `main` if the branch is not protected, otherwise open a PR
+- push
 
 # Status
 
-1.0+. Tagged 1.0.0 on 2026-02-26; 8 commits on main since. `make check`
-is green as of the golangci-lint v2.12.2 update.
+1.0+. Tagged 1.0.0 on 2026-02-26; 8 commits on main since. `make check` is green
+as of the golangci-lint v2.12.2 update.
 
 # Next Step
 
-Confirm `.gitea/workflows/check.yml` gates merges on `make check` so
-main cannot regress.
+Confirm `.gitea/workflows/check.yml` gates merges on `make check` so main cannot
+regress.
 
 # Completed Steps
 
+- 2026-09-22: Vendored the canonical prettier/format toolchain from the
+  `sneak/prompts` scaffold: added `.prettierrc` (tabWidth 4, proseWrap always),
+  pinned `package.json` + `yarn.lock` (prettier 3.8.1), taught
+  `script/bootstrap` to install a pinned node/yarn via a hash-verified nvm
+  archive, and switched `script/fmt` to the pinned prettier reading
+  `.prettierrc` (no inline flags) over `static/js/*.js` and `**/*.md`. Reflowed
+  all markdown to house style; `alpine.min.js` stays byte-identical (#203).
 - 2026-09-22: Fixed the flaky `t.TempDir` cleanup race in
-  `internal/service/webhook` by tracking the async deployment goroutine
-  in a `sync.WaitGroup` and exposing `WaitForDeployments`; tests now
-  synchronize on completion instead of sleeping (#198).
-- 2026-09-22: Linting now runs only in Docker. Added `Dockerfile.lint`
-  (pinned golangci-lint v2.12.2, cache-busted via a `GATE_RUN` build arg
-  so the linter always executes), reduced `script/lint` to building it,
-  dropped the golangci-lint install from `script/bootstrap`, and switched
-  the `Dockerfile` lint stage to invoke `golangci-lint` directly instead
-  of `make lint` to avoid docker-in-docker (#188).
-- 2026-09-22: Added `.prettierignore` so `make fmt` no longer rewrites
-  the vendored `static/js/alpine.min.js` bundle (#185).
-- 2026-09-22: Fixed the gosec G703 path-traversal finding in the deploy
-  log download handler by verifying the resolved path stays within the
-  deploy log directory before serving, returning 404 on escape (#177).
+  `internal/service/webhook` by tracking the async deployment goroutine in a
+  `sync.WaitGroup` and exposing `WaitForDeployments`; tests now synchronize on
+  completion instead of sleeping (#198).
+- 2026-09-22: Linting now runs only in Docker. Added `Dockerfile.lint` (pinned
+  golangci-lint v2.12.2, cache-busted via a `GATE_RUN` build arg so the linter
+  always executes), reduced `script/lint` to building it, dropped the
+  golangci-lint install from `script/bootstrap`, and switched the `Dockerfile`
+  lint stage to invoke `golangci-lint` directly instead of `make lint` to avoid
+  docker-in-docker (#188).
+- 2026-09-22: Added `.prettierignore` so `make fmt` no longer rewrites the
+  vendored `static/js/alpine.min.js` bundle (#185).
+- 2026-09-22: Fixed the gosec G703 path-traversal finding in the deploy log
+  download handler by verifying the resolved path stays within the deploy log
+  directory before serving, returning 404 on escape (#177).
 - 2026-09-22: `script/bootstrap` now installs a pinned `goimports`
-  (`golang.org/x/tools` v0.49.0) into `/usr/local/bin`, so `make fmt`
-  succeeds on a fresh machine after `make bootstrap` (#184).
-- 2026-09-09: Fixed four deployability blockers found by QA: CSRF origin
-  check over plain HTTP (`UPAAS_PLAINTEXT_HTTP`, #189), pulling the git
-  image when absent (#190), the env-var editor CSRF token lookup (#191),
-  and the port-mapping delete form's CSRF field (#192).
-- 2026-08-07: Updated golangci-lint to v2.12.2 (canonical
-  `.golangci.yml`, `Dockerfile` lint stage pin, `script/bootstrap`
-  release-archive pins) and fixed all resulting lint findings (noctx,
-  gosec, goconst, lll, dupl, nolintlint); `make check` green.
-- 2026-07-07 Adopted scripts-to-rule-them-all: `script/` entrypoints,
-  Makefile shims, README Entrypoints section
+  (`golang.org/x/tools` v0.49.0) into `/usr/local/bin`, so `make fmt` succeeds
+  on a fresh machine after `make bootstrap` (#184).
+- 2026-09-09: Fixed four deployability blockers found by QA: CSRF origin check
+  over plain HTTP (`UPAAS_PLAINTEXT_HTTP`, #189), pulling the git image when
+  absent (#190), the env-var editor CSRF token lookup (#191), and the
+  port-mapping delete form's CSRF field (#192).
+- 2026-08-07: Updated golangci-lint to v2.12.2 (canonical `.golangci.yml`,
+  `Dockerfile` lint stage pin, `script/bootstrap` release-archive pins) and
+  fixed all resulting lint findings (noctx, gosec, goconst, lll, dupl,
+  nolintlint); `make check` green.
+- 2026-07-07 Adopted scripts-to-rule-them-all: `script/` entrypoints, Makefile
+  shims, README Entrypoints section
 - 2026-03-11: Monolithic env var editing with bulk save (#158).
-- 2026-03-10: Webhook event history UI page (#164); added missing
-  Makefile docker and hooks targets plus test timeout (#159);
-  notification settings passed from create form (#160).
+- 2026-03-10: Webhook event history UI page (#164); added missing Makefile
+  docker and hooks targets plus test timeout (#159); notification settings
+  passed from create form (#160).
 - 2026-03-03: REPO_POLICIES compliance file set added (#155).
-- 2026-03-01: Module path changed to sneak.berlin/go/upaas (#143);
-  Dockerfile split into lint and build stages with forced lint
-  execution (#152, #154).
+- 2026-03-01: Module path changed to sneak.berlin/go/upaas (#143); Dockerfile
+  split into lint and build stages with forced lint execution (#152, #154).
 - 2026-02-26: 1.0.0 tagged; dashboard CSRFField crash fixed (#146).
-- 1.0 audit bug fixes (#120-#125): deferred rollback on commit error,
-  deployment log size cap, error path rendering, docker-compose bind
-  mount, domain type refactor.
+- 1.0 audit bug fixes (#120-#125): deferred rollback on commit error, deployment
+  log size cap, error path rendering, docker-compose bind mount, domain type
+  refactor.
 - CI simplified to docker build only (#130).
-- 2025-12-29 onward: core PaaS built out: deploys with real-time build
-  log streaming, container start/stop/restart and logs, TCP/UDP port
-  mapping, Alpine.js UI, Slack notifications, ULID app IDs, session
-  handling.
+- 2025-12-29 onward: core PaaS built out: deploys with real-time build log
+  streaming, container start/stop/restart and logs, TCP/UDP port mapping,
+  Alpine.js UI, Slack notifications, ULID app IDs, session handling.
 
 # Future Steps
 
diff --git a/package.json b/package.json
new file mode 100644
index 0000000..dc05cde
--- /dev/null
+++ b/package.json
@@ -0,0 +1,5 @@
+{
+  "devDependencies": {
+    "prettier": "3.8.1"
+  }
+}
diff --git a/script/bootstrap b/script/bootstrap
index 095afa8..58f9160 100755
--- a/script/bootstrap
+++ b/script/bootstrap
@@ -5,8 +5,12 @@
 # or apk (detected in that order); assumes NOTHING is present (not git,
 # make, or go). goimports is installed with `go install` at a pinned
 # version (integrity via the Go module checksum database) into
-# /usr/local/bin so it is on PATH. The linter is not installed here: it
-# runs only in Docker via script/lint, so docker is its sole prerequisite.
+# /usr/local/bin so it is on PATH. Node is used directly if installed;
+# otherwise it is installed at a pinned version via nvm (installing nvm
+# itself first, from a hash-verified release archive, never curl | sh),
+# then the pinned prettier from yarn.lock. The linter is not installed
+# here: it runs only in Docker via script/lint, so docker is its sole
+# prerequisite.
 set -eu
 
 ROOT="$(cd "$(dirname "$0")/.." && pwd -P)"
@@ -15,6 +19,12 @@ ROOT="$(cd "$(dirname "$0")/.." && pwd -P)"
 # golang.org/x/tools goimports, 2026-08-13. v0.49.0 requires Go 1.25 (matches
 # go.mod); v0.50.0 needs Go 1.26. Integrity via the Go module checksum database.
 GOIMPORTS_VERSION="v0.49.0"
+# Node/yarn toolchain, 2026-07-06.
+NODE_VERSION="22.17.0"
+NVM_VERSION="0.40.3"
+# sha256 of https://github.com/nvm-sh/nvm/archive/refs/tags/v0.40.3.tar.gz
+NVM_SHA256="5f4d6aaa04a177dc93c985e31dbc411ab6b8c6e1e21d8015dbc1372625fcd1d0"
+YARN_VERSION="1.22.22"
 
 PKGMGR=""
 SUDO=""
@@ -56,6 +66,21 @@ 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:   $actual" >&2
+        exit 1
+    fi
+}
+
 # goimports is not packaged uniformly across nix/apt/brew/apk, so install it
 # with `go install` at a pinned version and place the binary in /usr/local/bin
 # so it is on PATH regardless of shell config. Requires go, which main
@@ -69,6 +94,54 @@ ensure_goimports() {
     rm -rf "$tmp"
 }
 
+# nvm is a bash script; run a command in a bash with nvm loaded
+nvm_sh() {
+    bash -c ". \"\$HOME/.nvm/nvm.sh\" && $*"
+}
+
+ensure_nvm() {
+    [ -s "$HOME/.nvm/nvm.sh" ] && return 0
+    # nvm prerequisites; nvm itself requires bash
+    if missing bash; then pkg_install bash bash bash bash; fi
+    if missing curl; then pkg_install curl curl curl curl; fi
+    if missing git; then pkg_install git git git git; fi
+    tmp="$(mktemp -d)"
+    curl -fsSL -o "$tmp/nvm.tar.gz" \
+        "https://github.com/nvm-sh/nvm/archive/refs/tags/v${NVM_VERSION}.tar.gz"
+    verify_sha256 "$tmp/nvm.tar.gz" "$NVM_SHA256"
+    mkdir -p "$HOME/.nvm"
+    tar -xzf "$tmp/nvm.tar.gz" -C "$HOME/.nvm" --strip-components=1
+    rm -rf "$tmp"
+}
+
+ensure_node() {
+    if ! missing node; then return 0; fi
+    ensure_nvm
+    nvm_sh "nvm install $NODE_VERSION"
+}
+
+ensure_yarn() {
+    if ! missing yarn; then return 0; fi
+    if ! missing corepack; then
+        corepack enable
+        corepack prepare "yarn@$YARN_VERSION" --activate
+    elif [ -s "$HOME/.nvm/nvm.sh" ]; then
+        nvm_sh "nvm use $NODE_VERSION >/dev/null && corepack enable && \
+            corepack prepare yarn@$YARN_VERSION --activate"
+    else
+        npm install -g "yarn@$YARN_VERSION"
+    fi
+}
+
+install_js_deps() {
+    if missing yarn && [ -s "$HOME/.nvm/nvm.sh" ]; then
+        nvm_sh "nvm use $NODE_VERSION >/dev/null && cd \"$ROOT\" && \
+            yarn install --frozen-lockfile"
+    else
+        yarn install --frozen-lockfile
+    fi
+}
+
 main() {
     cd "$ROOT"
 
@@ -80,6 +153,11 @@ main() {
     if missing go; then pkg_install go golang go go; fi
     ensure_goimports
 
+    # Node toolchain and pinned prettier
+    ensure_node
+    ensure_yarn
+    install_js_deps
+
     # The linter runs only in Docker (script/lint). Warn, don't fail: the
     # rest of the repo works without it.
     if missing docker; then
diff --git a/script/fmt b/script/fmt
index 2c9c55c..d7ab4f3 100755
--- a/script/fmt
+++ b/script/fmt
@@ -4,11 +4,34 @@ set -eu
 
 ROOT="$(cd "$(dirname "$0")/.." && pwd -P)"
 
+# Must match the pin in script/bootstrap.
+NODE_VERSION="22.17.0"
+
+# script/bootstrap installs node and yarn under nvm and leaves neither
+# on the PATH of the shell that called it, so resolve the pinned
+# toolchain here the way bootstrap's own install step does. nvm is a
+# bash script, hence the subshell.
+run_yarn() {
+    if command -v yarn >/dev/null 2>&1; then
+        yarn "$@"
+        return
+    fi
+    if [ ! -s "$HOME/.nvm/nvm.sh" ]; then
+        echo "fmt: no yarn; run script/bootstrap first" >&2
+        exit 1
+    fi
+    bash -c '. "$HOME/.nvm/nvm.sh" && nvm use "$1" >/dev/null &&
+        shift && exec yarn "$@"' bash "$NODE_VERSION" "$@"
+}
+
 main() {
     cd "$ROOT"
     gofmt -s -w .
     goimports -w .
-    npx prettier --write --tab-width 4 static/js/*.js
+    # Pinned prettier reads settings from .prettierrc (tabWidth 4,
+    # proseWrap always); .prettierignore keeps alpine.min.js untouched.
+    # Globs are quoted so prettier expands them, not the shell.
+    run_yarn run prettier --write 'static/js/*.js' '**/*.md'
 }
 
 main "$@"
diff --git a/yarn.lock b/yarn.lock
new file mode 100644
index 0000000..d846639
--- /dev/null
+++ b/yarn.lock
@@ -0,0 +1,8 @@
+# THIS IS AN AUTOGENERATED FILE. DO NOT EDIT THIS FILE DIRECTLY.
+# yarn lockfile v1
+
+
+prettier@3.8.1:
+  version "3.8.1"
+  resolved "https://registry.yarnpkg.com/prettier/-/prettier-3.8.1.tgz#edf48977cf991558f4fcbd8a3ba6015ba2a3a173"
+  integrity sha512-UOnG6LftzbdaHZcKoPFtOcCKztrQ57WkHDeRD9t/PTQtmT0NHSeWWepj6pS0z/N7+08BHFDQVUrfmfMRcZwbMg==