Rewrite TODO.md sentence by sentence (closes #558)

Rewritten from scratch, sections kept, every statement checked against the code. Passed independent review in round 4.

Model: fable-5-1 (writing); opus-5-5 (review, merge)

TODO.md

@@ -1,72 +1,77 @@
 # Workflow
 
-One issue per unit of work, one branch and one PR per issue:
+One issue per unit of work, and one branch and one PR per issue:
 
-- ensure a tracked issue exists with a definition of done
-- branch from `next` (never from `main`)
-- do the work; open a PR based on `next` (never on `main`)
-- pass an independent review, then the manager squash-merges into `next`
-- push; nothing stays local-only
+- make sure a tracked issue exists with a definition of done
+- branch from `next`, never from `main`
+- do the work and push the branch
+- open a PR with base `next`, never `main`
+- pass an independent review
+- the repository manager squash-merges it into `next`
 
-`next` is the branch for the next milestone and must stay green and mergeable to
-`main` without notice. One `next` -> `main` PR accumulates the milestone;
-releases are cut from `main` separately.
+The repository manager is the role that merges each issue's PR into `next`.
+Nothing stays local-only: every commit is pushed.
 
-The tracker (https://git.eeqj.de/sneak/webhooker/issues) is the record of what
-is done and what is under way. This file keeps no list of either.
+`next` is the branch for the next milestone. It must stay green and mergeable
+into `main` at all times. A milestone's work reaches `main` through one PR from
+`next`. The owner, @sneak, merges that PR. Cutting a release from `main` is a
+separate step after that.
+
+The tracker (https://git.eeqj.de/sneak/webhooker/issues) records what is done
+and what is under way. This file keeps no list of either.
 
 # Status
 
 What is still open for 1.0.0 is in its milestone
-(https://git.eeqj.de/sneak/webhooker/milestone/9). `v1.0.0` is not tagged, and
-only @sneak tags it.
+(https://git.eeqj.de/sneak/webhooker/milestone/9). `v1.0.0` is not tagged. Only
+@sneak tags it.
 
-Delivery is at-least-once by design, not by accident: a send whose result row
-does not land is attempted again, so a receiver can see a duplicate. That is
-deliberate — the alternative is a silent lost delivery — and the README says so
-under Rationale. It is not a defect to re-file.
+Delivery is at least once by design. When webhooker cannot record the outcome of
+a delivery, it sends that delivery again. The target can then receive the same
+event twice. The alternative is a lost delivery that nothing reports. The README
+says so. Such a duplicate is not a defect to re-file.
 
 # Next Step
 
 @sneak runs webhooker in limited production, then tags `v1.0.0`. Merging `next`
-into `main` is a separate act from tagging and waits on neither of those: `next`
-is kept mergeable at all times, which is the point of the branch.
+into `main` is a separate act. It waits on neither the production run nor the
+tag.
 
 # Future Steps
 
-- Per-webhook rate limits, set in the web UI and enforced in the receiver
-  handler, on top of the receiver's existing limits, which `RECEIVER_RATE_LIMIT`
-  sets for the whole server (see Rate Limiting in the README)
-- API key authentication for programmatic access (the `APIKey` model exists, but
-  nothing creates a key and no middleware checks one)
-- REST API v1
-    - CRUD for webhooks, entrypoints, targets
+- Per-webhook rate limits, set in the web UI and enforced at the entrypoint.
+  Today `RECEIVER_RATE_LIMIT` is the only rate-limit setting. It is how many
+  requests per minute one client address may send to one entrypoint. The same
+  address is also capped at ten times that across all entrypoints together.
+- API key authentication for programmatic access. The `APIKey` model and its
+  `api_keys` table exist. Nothing creates a key and nothing checks one.
+- REST API v1. `/api/v1` is mounted with no routes today.
+    - CRUD for webhooks, entrypoints and targets
     - event viewing and filtering endpoints
     - event redelivery endpoint
     - OpenAPI specification
 - Analytics in the web UI: response times summarised per webhook or per target,
-  and figures for all webhooks together. The webhook page already shows event,
-  delivery and failure counts and failure percentages, the target list counts
-  each target's deliveries, the event log and each event's page show every
-  attempt's duration, and `/metrics` carries server-wide counts and delivery
-  durations
-- A remember-me option at login. Every session already survives a browser
-  restart: it lasts up to 7 days, and ends sooner after `SESSION_IDLE_TIMEOUT`
-  (default 24 hours) without activity
-- Password reset flow for a forgotten password over the web. The authenticated
-  password _change_ flow already landed, and a lost password is recoverable from
-  the console with `webhooker resetpw`
-  (https://git.eeqj.de/sneak/webhooker/issues/208)
+  and figures for all webhooks together. Today the webhook page shows event,
+  delivery and failure counts and failure percentages. The target list counts
+  each target's deliveries. The event log shows every attempt's duration.
+  `/metrics` carries server-wide counts and delivery durations.
+- A remember-me option at login. Today every session survives a browser restart.
+  It lasts up to 7 days. It ends sooner after `SESSION_IDLE_TIMEOUT` (default 24
+  hours) without use.
+- Password reset over the web for a forgotten password. Today a signed-in user
+  can change their password. A lost password is reset from the command line with
+  `webhooker resetpw` (https://git.eeqj.de/sneak/webhooker/issues/208).
 - Later, nice to have
     - email delivery target type
     - SNS and S3 delivery targets
-    - data transformations (e.g. a configurable Slack message format; the Slack
-      target sends one fixed format today)
-    - JSONL file delivery with periodic S3 upload (the `database` target already
-      archives events to SQLite files, rotated hourly, daily or monthly if set,
-      and the webhook page offers them as one gzipped JSON download)
+    - data transformations, such as a configurable Slack message format. The
+      Slack target sends one fixed format today.
+    - JSONL file delivery with periodic S3 upload. Today an archive target
+      writes events to SQLite files. An archive target can rotate those files
+      hourly, daily or monthly. The webhook page offers them as one gzipped JSON
+      download.
     - webhook event search, and filtering beyond the event log's failed and
       pending views
-    - multi-user with role-based access control (each webhook already belongs to
-      one account, but there is only the account made at first boot and no way
-      to add another)
+    - multi-user with role-based access control. Today each webhook belongs to
+      one account. Only the account made at first boot exists. There is no way
+      to add another.