heartbeat: statuses: write for the worker's test-run check

Co-Authored-By: Claude Fable 5.1 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01UpT7eWzeLhRwuYmsSQnbRb

.github/workflows/heartbeat.yml

@@ -16,6 +16,7 @@ permissions:
   issues: write
   pull-requests: write
   checks: read
+  statuses: write     # a Venice worker's test run is recorded as the PR's check
 concurrency:
   group: heartbeat
   cancel-in-progress: false