core: flag stale PR checks as failing

STALE was absent from the negative check conclusions. The rollup reported passing while the server's unknown-value guard reduced it to pending, leaving expired checks In review instead of Needs you. Cover the pure rollup and the real PR refresh IPC path.
61efc70230Lucenx9 committed on 10/15/2026, 5:45:10 PMparent6c6234d

Checks

All checks passed
2 files changedLine totals unavailable