hermes - 💡(How to fix) Fix Bug: slash_worker lifecycle gaps and system fragility observed during intensive Dashboard usage (#21370)

During high-frequency interaction tests with hermes dashboard on macOS, we observed a failure state that highlights critical gaps in subprocess lifecycle management. While #21370 identifies the leak, our experience suggests that these leaks contribute to a state of system fragility.

Observations

1. Accumulation: Intensive UI usage orphans dozens of slash_worker processes (parented to PID 1).
2. Update Collision: A routine "hermes update" was executed while orphans were present. The update became "stuck" and the environment was corrupted.
3. Failure State: Subsequent commands failed with .../venv/bin/python3: No module named pip.
4. Recovery Issue: Orphans survived atexit hooks and remained active, complicating manual recovery and environment sync.

Architectural Gaps

• Unmanaged Resource: slash_worker is spawned outside tools.process_registry, making it invisible to global teardown logic.
• Fragile Cleanup: Reliance on atexit is insufficient for update-induced restarts or hard crashes.
• Lack of Self-Termination: The worker cannot detect when its parent has died.

Proposed Fix

I have verified a "Defense-in-Depth" solution on macOS following AGENTS.md:

1. Unified Management: Extended ProcessRegistry with register_host_process to track these workers.
2. Fingerprinted Watchdog: Added a thread to slash_worker.py monitoring parent PID + create_time.

I have the patch ready for PR. Please let me know if you would like me to submit it.