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

The producer only de-announced on close, and that close-resolve required the
label to still be present — so unlabel-then-merge left the request stranded
"open" on the town-crier bus forever. Add `unlabeled` to the trigger types and
fire /resolve when the "Agent Review Requested" label is removed (the bus
no-ops an unknown pr_url, so it's always safe). Announce side unchanged.

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01NzAm5CqhSQTzD3PBuZHyfY

Author: jasperboerhof

.github/workflows/announce-pr.yml

@@ -6,8 +6,8 @@
 #
 # Produces BOTH sides of a request's lifecycle, so the bus never drifts from GitHub:
 #   - announce: when "Agent Review Requested" lands on a PR, tell the crier once.
-#   - resolve:  when that PR closes/merges, retire its thread — otherwise a landed PR
-#               sits "open" on the bus forever (there is no GitHub->bus merge sync).
+#   - resolve:  when that PR closes/merges or its review label is removed, retire its thread —
+#               otherwise a landed PR sits "open" on the bus forever (there is no GitHub->bus merge sync).
 # Joined harnesses pick up open requests from the bus — this workflow does NOT poll or review.
 #
 # Failure policy (two distinct modes, so a real problem is never silently masked):
@@ -22,7 +22,7 @@ permissions: {}
 
 on:
   pull_request:
-    types: [labeled, closed]
+    types: [labeled, unlabeled, closed]
 
 jobs:
   announce:
@@ -57,21 +57,28 @@ jobs:
             || echo "::warning::town-crier announce failed (transient bus issue?) — not blocking the PR"
 
   resolve:
-    if: github.event.action == 'closed' && contains(github.event.pull_request.labels.*.name, 'Agent Review Requested')
+    if: (github.event.action == 'closed' && contains(github.event.pull_request.labels.*.name, 'Agent Review Requested')) || (github.event.action == 'unlabeled' && github.event.label.name == 'Agent Review Requested')
     runs-on: ubuntu-latest
     steps:
       - name: Resolve on the crier
         env:
           CRIER_URL: ${{ vars.TOWN_CRIER_URL }}
           CRIER_TOKEN: ${{ secrets.TOWN_CRIER_TOKEN }}
           PR_URL: ${{ github.event.pull_request.html_url }}
+          ACTION: ${{ github.event.action }}
           MERGED: ${{ github.event.pull_request.merged }}
         run: |
           if [ -z "$CRIER_URL" ] || [ -z "$CRIER_TOKEN" ]; then
             echo "::error::town-crier not provisioned — set the TOWN_CRIER_URL variable + TOWN_CRIER_TOKEN secret"
             exit 1
           fi
-          NOTE=$([ "$MERGED" = "true" ] && echo "merged" || echo "closed without merge")
+          if [ "$ACTION" = "unlabeled" ]; then
+            NOTE="review label removed"
+          elif [ "$MERGED" = "true" ]; then
+            NOTE="merged"
+          else
+            NOTE="closed without merge"
+          fi
           curl -fsS --max-time 10 -X POST "$CRIER_URL/resolve" \
             -H "Authorization: Bearer $CRIER_TOKEN" \
             -H "Content-Type: application/json" \