Stale directory lock not released after session stops (blocks subsequent launches)

[doink-kindo]

Bug Report

Session: edfb39e1 (stopped within ~4min of launch)
Symptom: After session edfb39e1 stopped, agentctl still reports its directory as 'in use', blocking new launches for different worktrees with the same error:

Directory in use by session edfb39e1. Use --force to override.

Worktrees affected (different from edfb39e1's worktree ~/code/mono):

• ~/code/mono-doink-eng-8991-filter-agent-runs-by-status
• ~/code/mono-auto-ENG-10035

Steps to reproduce:

1. Launch claude-code agent via patrol-launch-ci-fix.sh → session edfb39e1, CWD ~/code/mono
2. Session stops quickly (< 4 min)
3. Attempt to launch another agent in a different worktree under ~/code/mono-*
4. Error: 'Directory in use by session edfb39e1'

Expected: After session stops, the directory lock should be released.
Actual: Lock persists even after session is stopped; agentctl stop edfb39e1 --force exits 1 without releasing the lock.

Likely cause: The directory lock may be on the parent ~/code/mono directory (prefix match?) rather than the exact worktree, causing all ~/code/mono-* paths to be blocked.

Workaround: None found. --force on patrol-launch-ci-fix.sh did not help.

Discovered during patrol run on 2026-06-23T07:02 UTC.