hermes - 💡(How to fix) Fix [Bug]: Archived kanban board instantly resurrected by gateway dispatcher — Archive appears to not work

Describe the bug

Archiving a kanban board from the dashboard (or via CLI hermes kanban boards rm) appears to have no effect — the board stays visible or reappears within seconds.

To Reproduce

1. Have a kanban board with active tasks
2. Run gateway with dispatcher enabled (kanban.dispatch_in_gateway: true)
3. Archive the board from dashboard (click Archive) or CLI (hermes kanban boards rm <slug>)
4. The board either never disappears from the dashboard, or reappears within ~3 seconds

Expected behavior

Archived board should disappear from the board list and NOT reappear until explicitly restored.

Root Cause

The gateway's kanban dispatcher (_kanban_dispatcher_watcher) and notifier (_kanban_notifier_watcher) work in a two-phase loop:

1. Enumerate boards via list_boards(include_archived=False)
2. Call connect(board=slug) on each

If a board is archived between step 1 and step 2, connect() — which does mkdir(exist_ok=True) on the board directory — recreates an empty board directory, resurrecting the archived board.

This affects three code paths:

• _kanban_notifier_watcher (board enumeration loop)
• _kanban_dispatcher_watcher._tick_once_for_board (per-board dispatch)
• _kanban_dispatcher_watcher._ready_nonempty (cheap probe)

Evidence

From gateway.log showing the dispatcher failing on an empty resurrected board:

kanban dispatcher: tick failed on board token-harvest-20260527
sqlite3.OperationalError: no such table: tasks

_archived/ accumulated 22 copies of 4 boards from repeated archive attempts (cleaned up to 1 per board).

Fix

Add board_dir(slug).exists() guard before connect() calls — if the board was archived since list_boards(), skip it instead of recreating. See PR #35208.