Salvages #23790 by @thewillhuang. Adds detect_stale_running() to
the dispatcher cycle. Running tasks that have been started for longer
than dispatch_stale_timeout_seconds (default 14400 = 4h) without a
heartbeat in the last hour are auto-reclaimed to ready.
- New config kanban.dispatch_stale_timeout_seconds (default 14400, 0 disables)
- New 'stale' field on DispatchResult
- detect_stale_running() in kanban_db.py with heartbeat freshness check
- Records outcome='stale' on run close + 'stale' event; ticks failure counter
- Wires config through gateway embedded dispatcher
- Updates _cmd_dispatch verbose/JSON output and daemon logging
Resolved test-file end-of-file conflict by appending both halves.
e286e68756