test: capability check for branch/push/PR access

Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01VnwxgZTcBvf1GhzfJB5fTR
0c5888b5d7Claude committed on 9/15/2026, 7:32:39 PMparent086bd76
1 file changedLine totals unavailable