What: More reliable version lock system that tracks process IDs instead of just file modification times. Details:
- Detects if locking process is actually running
- Better stale lock cleanup on startup
- Enhanced error reporting showing which PID holds a lock
- Automatic cleanup of locks from crashed processes
- Feature-flagged via
tengu_pid_based_version_locking - Evidence:
ai()at line 397742,K91()at line 397747,V91()cleanup at line 397896