ci(town-crier): resolve on unlabel — de-announce when the review label is removed

[jasperboerhof]

What

Make the town-crier producer workflow (.github/workflows/announce-pr.yml) also de-announce a PR when its review label is removed — not just on close/merge.

Four edits:

1. on.pull_request.types gains unlabeled.
2. The resolve: job if: fires on either closed (with the label still present) or unlabeled of Agent Review Requested.
3. The resolve step gains an ACTION env var and computes NOTE across three cases (review label removed / merged / closed without merge).
4. Header comment amended to mention label removal.

Why

The producer only de-announced on close, and that close-resolve required the Agent Review Requested label to still be present. So unlabel-then-merge left the request stranded "open" on the town-crier bus forever — there is no GitHub→bus merge sync, so nothing else ever retired it.

Removing the label now immediately POSTs /resolve. The bus no-ops an unknown pr_url, so firing /resolve on an already-resolved or never-announced PR is always safe. The announce side is unchanged.

Verification

• python3 -c "import yaml; yaml.safe_load(open('.github/workflows/announce-pr.yml'))" → YAML OK.
• No workflow/YAML/shell linter in this repo's CI (grep -rilE 'actionlint|yamllint|shellcheck' .github/ → none); composer scripts are PHP-only (test, phpstan, format) and don't touch this file.
• Diff is exactly the four intended edits, 2-space indentation preserved to match the file.

🤖 Generated with Claude Code

https://claude.ai/code/session_01NzAm5CqhSQTzD3PBuZHyfY

[Goosterhof]

Clean follow-on. The unlabeled addition is correctly guarded and introduces no new injection surface — verified against the four edits the body claims, no drift.

• Unlabel guard is correct. The resolve if: keys the unlabel branch on github.event.label.name == 'Agent Review Requested', which on the unlabeled action is the label that was just removed. Stripping an unrelated label (a wip/priority tag) won't fire a spurious /resolve — the false-de-announce trap is closed.
• Triggers preserved. types: [labeled, unlabeled, closed] extends rather than replaces — announce (labeled) and close-resolve (closed) survive.
• No new injection vector. The added ACTION env is github.event.action (a fixed enum, not attacker-controllable), and NOTE reaches curl via jq --arg. github.event.label.name is used only inside the if: expression (GitHub-evaluated), never interpolated into a run: shell.
• Spine intact. permissions: {}, pull_request (not pull_request_target), and the loud-on-config-error / warn-on-bus-hiccup fail-open policy all carried through unchanged.

No findings. The body's "bus no-ops an unknown pr_url, so a redundant /resolve is safe" reasoning is sound, and CI is green (announce + check 8.4/8.5 pass; resolve correctly skips on this event).

Automated war-room agent review — posted because this PR carries the Agent Review Requested label.