ci: a release publishes a changelog, not an image (318 step 7)

Step 2 took the build consequence away from a `v*` tag — `main` has already
built and published the commit by the time anyone tags it, and rebuilding
would re-push `:c-<sha>`, which rule 145 forbids even when the source
matches. That left the tag with nothing to do at all.

This is the job it has instead. Step 6 put the derived version in the
Settings footer, so an operator can say WHICH build they are running; this
says what is in it that was not in the one they ran last month. Both halves
of one question (note #3127 §5).

The previous release is found by walking ANCESTRY, not by sorting a list.
That is load-bearing here specifically: rule 148 moved the tag shape from
`v26.05.22.0` to `v2026.08.28.2208`, and lexicographically `v2026...` sorts
BEFORE `v26...` — the third character is `0` against `6`. A sorted
implementation would reach back past every new-shape tag to the newest
old-shape one and publish months of commits as "changes since", looking
entirely correct while doing it. `git describe --exclude` is immune to the
shape change, and reachability is the more honest question anyway.

The publisher GETs and PATCHes rather than POSTing and recovering the id
from a 409 — note #3127 §6.7, which is ThoughtSync #2182's bug. A `v*` tag
is created once so the conflict path is rare, but "rare" is how that one
survived to be found somewhere else.

Cross-checks are reported on the release, not enforced. The tag is already
pushed by the time this runs, so failing would leave the operator with a tag,
no release, and a red lane to explain it — while the release is still the
useful object. It says so at the top when the tag names a version the web
image does not report, or when the commit is not on `main` and the `:c-`
rollback refs it lists were never published.

Nothing runs on a schedule and nothing auto-tags on merge. Release tags are
bookmarks (note #3127 §0); FC went twelve weeks without one and nothing was
wrong.

Also here:
- `scripts/` joins the ruff lane. release_notes.py runs only on a tag push,
  so a syntax error there would otherwise surface at the one moment nobody
  wants to be debugging a workflow.
- version.spec.js reads the workflow directory instead of listing three
  files by hand. Its own comment says the assertion should survive consumers
  coming and going; the hardcoded list was the part that could not, and
  release.yml would have joined the directory without joining the check.

Tests build a synthetic history spanning the tag-shape change rather than
leaning on this repo's tags, so the span assertion holds whether or not a
checkout brought the tags along — a span test that quietly skips is worse
than one that fails.

.forgejo/workflows/ci.yml

@@ -35,7 +35,10 @@ jobs:
       - name: Ruff lint
         # agent/ included so the GPU-agent is linted before its image is built
         # (build.yml only `docker build`s it — this is where it gets checked).
-        run: ruff check backend/ tests/ alembic/ agent/
+        # scripts/ likewise: release_notes.py runs only on a tag push, so a
+        # syntax or import error there would otherwise surface at the one
+        # moment nobody wants to debug a workflow.
+        run: ruff check backend/ tests/ alembic/ agent/ scripts/
       - name: Agent syntax check
         # The agent's runtime deps (torch/transformers/ultralytics) aren't in the
         # CI image, so we can't import it — but compileall parses every module,

.forgejo/workflows/release.yml

@@ -0,0 +1,80 @@
+name: Release
+
+# A `v*` tag publishes a changelog. It does NOT build anything.
+#
+# Milestone 318 step 2 removed the tag trigger from build.yml: by the time
+# anyone tags a commit, `main` has already built and published it, and a
+# rebuild would re-push `:c-<sha>` — which rule 145 forbids even when the
+# source matches, since image configs carry timestamps and "same source" does
+# not mean "same manifest". That left the tag with no consequence at all.
+#
+# This is the consequence it has instead. Step 6 put the derived version in the
+# Settings footer, so an operator can say WHICH build they are running; this
+# says what is IN it that was not in the one they ran last month. Both halves
+# of one question (note #3127 §5).
+#
+# Nothing here runs on a schedule and nothing auto-tags on merge. Release tags
+# are bookmarks — cut one when you will want to point at that day by name,
+# otherwise don't (note #3127 §0). FC went twelve weeks between v26.06.04.0 and
+# the next one and nothing was wrong. A schedule would turn an optional
+# bookmark back into ceremony, which is the thing this milestone is removing.
+#
+# Cutting the tag is an explicit operator action under rule 2 ("`main` — never
+# without explicit request", which since 2026-08-28 covers PR, merge and tag
+# alike). This lane only decides what happens once they do.
+#
+# Requires repo secret RELEASE_TOKEN with the `write:release` scope — the same
+# PAT build.yml uses for the ext-<version> XPI asset cache.
+
+on:
+  push:
+    tags: ['v*']
+  # So a release body can be regenerated after the fact — the publisher PATCHes
+  # an existing release rather than falling through on a conflict, so re-running
+  # this on a tag rewrites the body instead of silently keeping the first one
+  # (note #3127 §6.7).
+  workflow_dispatch:
+    inputs:
+      tag:
+        description: 'Tag to (re)publish notes for'
+        required: true
+
+jobs:
+  changelog:
+    runs-on: python-ci
+    container:
+      image: git.fabledsword.com/bvandeusen/ci-python:3.14
+    steps:
+      - uses: actions/checkout@v4
+        with:
+          # Load-bearing twice over: the previous release is found by walking
+          # ancestry back through the tag graph, and the cross-check against
+          # the derived web version calls artifacts.sh, which reads commit
+          # times. A shallow clone would find no previous tag and emit the
+          # entire history as the changelog — plausible-looking and wrong.
+          fetch-depth: 0
+          ref: ${{ github.event.inputs.tag || github.ref }}
+
+      # The `:c-<sha>` rollback refs are only real if `main` built this commit.
+      # The script checks that against origin/main and downgrades the claim to
+      # "unverified" when it cannot resolve one; fetching it here means that
+      # downgrade stays an actual signal instead of firing on every release.
+      - name: Make main's history resolvable
+        run: git fetch --no-tags --quiet origin +main:refs/remotes/origin/main || true
+
+      # TAG goes through the environment, not through `${{ }}` inside the
+      # run block. The value is operator-supplied, and an expression expanded
+      # into a shell line is expanded BEFORE the shell sees it — there is no
+      # quoting that makes that safe. On a tag push it is empty and the script
+      # falls back to GITHUB_REF.
+      - name: Publish the derived changelog
+        env:
+          RELEASE_TOKEN: ${{ secrets.RELEASE_TOKEN }}
+          TAG: ${{ github.event.inputs.tag }}
+        run: |
+          set -eu
+          if [ -n "${TAG:-}" ]; then
+            python3 scripts/release_notes.py "$TAG"
+          else
+            python3 scripts/release_notes.py
+          fi