Follow-up on the cherry-picked gitlock work (#80501 by @RGerrish, covering
the #75133 / #75168 wedge first reported and fixed by @RelaxJonh):
- Drop the PR's ancestor-check halves in banner.py, update-count.ts and
main.ts: superseded by the compare-API status recovery that landed in
#86257/#86331 (ahead_by == 0 already reports local-ahead as up to date).
The salvaged update_cmd.py check path keeps main's compare-API structure
instead of the PR's tip-SHA-plus-ancestry print.
- Keep and wire clear_stale_git_locks() at the remaining wedge sites the
original PR targeted: hermes update apply, hermes update --check, and the
passive banner check.
- Add the desktop counterpart (electron/gitlock.ts) so checkUpdates() heals
the same wedge instead of reporting fetch-failed forever; mirrored
age + git-process guards; vitest coverage.
E2E verified: real --depth 1 clone with an aged .git/shallow.lock reproduces
"Unable to create '.git/shallow.lock': File exists"; clear_stale_git_locks
removes it and the fetch succeeds; a fresh lock (in-flight fetch) is
preserved.
