Merge pull request #9: ui-test singleton queue

Replaces per-sha cancel-in-progress (which fired spurious self-cancels) with a singleton queueing group. ui-test #74 (push) and #75 (pull_request) both green at ~2m, queue-not-cancel verified.

.gitea/workflows/ui-test.yaml

@@ -16,14 +16,17 @@ on:
       - '.gitea/workflows/ui-test.yaml'
       - '!**/*.md'
 
-# Playwright launches its own `pnpm dev` on :5173. In host-mode the
+# Playwright launches its own `pnpm dev` on :5173, and in host-mode
-# runner shares the host's port namespace, so two parallel ui-test
+# the runner shares the host's port namespace with every other job,
-# jobs (e.g. a push event racing with a pull_request event for the
+# so two parallel ui-test runs collide on EADDRINUSE. Serialise via a
-# same commit) collide on EADDRINUSE. Group by the head commit so
+# singleton concurrency group with queueing — new runs wait their
-# push and pull_request events for the same sha share one bucket.
+# turn instead of cancelling the in-progress one. cancel-in-progress
+# is explicitly false because Gitea has shown spurious self-cancel
+# behaviour under cancel-in-progress: true even when no other run
+# shares the group.
 concurrency:
-  group: ui-test-${{ gitea.event.pull_request.head.sha || gitea.sha }}
+  group: ui-test-singleton
-  cancel-in-progress: true
+  cancel-in-progress: false
 
 jobs:
   test: