Fix automerge: wait for full CI workflow, not individual checks

Changed trigger from check_suite to workflow_run on CI workflow.
This ensures all jobs (typecheck, lint, test, build, e2e) pass
before auto-merging, not just the first check to complete.

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

.github/workflows/automerge.yml

@@ -1,7 +1,8 @@
 name: Automerge
 
 on:
-  check_suite:
+  workflow_run:
+    workflows: ["CI"]
     types: [completed]
   pull_request:
     types: [labeled]
@@ -15,7 +16,7 @@ jobs:
     runs-on: ubuntu-latest
     if: >
       github.event_name == 'pull_request' ||
-      (github.event_name == 'check_suite' && github.event.check_suite.conclusion == 'success')
+      (github.event_name == 'workflow_run' && github.event.workflow_run.conclusion == 'success')
     permissions:
       contents: write
       pull-requests: write