- _git_run(network=True) now carries a 300s timeout; a dead-stalled fetch
(HTTP/2 to GitHub on some networks, black-holed proxy) becomes a failed run
whose stderr names the stall instead of an update pinned on
'Fetching updates...' forever (#93759, #95777). Local git stays unbounded.
- The apply path prunes stale .git/shallow grafts alongside its existing
lock/tmp_pack cleanup, so installs that already accumulated grafts from
past depth-1 checks (#105951: 57 entries) heal on their next update, not
only on --check.