Kill Kanban worker process trees on Windows timeout

[sdgdllc]

Summary

• On Windows, terminate Kanban worker process trees with taskkill /T /F when max-runtime or reclaim cleanup kills a worker.
• Preserve the existing signal_fn hook path for unit tests and non-Windows behavior.
• Record process-tree cleanup metadata in timeout/reclaim event payloads.

Why

A dispatcher timeout can kill only the recorded worker PID while leaving stdio MCP descendants alive (node, npx, Playwright MCP, AgentMemory MCP, local runtime MCP). That leaks tool servers after a Kanban card times out and degrades the host.

Verification

• C:\Users\m_t_c\.hermes-sdgd\venv\Scripts\python.exe -m pytest -o addopts= -p no:timeout tests\hermes_cli\test_kanban_db.py -k "max_runtime or terminate_worker_pid"

[teknium1]

Thanks for addressing a real Windows cleanup gap: current main still uses direct PID signaling in hermes_cli/kanban_db.py:6163-6197 and :6358-6378, while the established Windows tree-kill convention is taskkill /T /F in gateway/status.py:98-125.

Problems

• hermes_cli/kanban_db.py:5148 uses subprocess.CREATE_NO_WINDOW directly. The new test sets _IS_WINDOWS=True while running under Linux (tests/hermes_cli/test_kanban_db.py:941-945), where that attribute does not exist, so the test raises AttributeError before reaching the mocked taskkill call.
• The PR diff includes unrelated channel-directory, Discord, and Git-Bash fixes. gh pr diff 49374 --name-only lists nine files, while commit 8ef3f040245c itself changes only the Kanban implementation and its test.

Suggested changes

• Use the platform-safe hide-flags helper already used by gateway/status.py:108-117, then keep the mocked-Windows test runnable on Linux.
• Salvage the focused Kanban change onto current main, applying it to both enforce_max_runtime and _terminate_reclaimed_worker so timeout and reclaim cleanup share the same tree-kill behavior.

Automated hermes-sweeper review.

[teknium1]

CREATE_NO_WINDOW is absent from Linux's subprocess module. Because the new test sets _IS_WINDOWS=True on Linux, this line raises AttributeError before the mocked taskkill runs. Use the platform-safe hide-flags helper or a guarded lookup so the test remains cross-platform.