ebe04c66cd
`sqlite3.Connection.__exit__` commits/rollbacks but does NOT close the underlying FD. `with kb.connect() as conn:` in long-lived processes (gateway `run_slash`, dashboard `decompose_task_endpoint`) therefore leaks one FD to `kanban.db` per call. After enough operations the gateway dies with `[Errno 24] Too many open files` (~4 days uptime in the production report — #33159). Fix: add a `connect_closing()` context manager in `hermes_cli/kanban_db` that wraps `connect()` with a real `try/finally: conn.close()`. Switch the 42 leak-prone call sites in `hermes_cli/kanban.py` (35), `hermes_cli/kanban_decompose.py` (4), and `hermes_cli/kanban_specify.py` (3) over to it. `kanban.py` matters because `run_slash` (called from the gateway for every `/kanban` slash command) parses argparse and dispatches to those `_cmd_*` functions in-process — each one was leaking one FD per invocation. Tests inside `tests/` are untouched: short-lived processes where OS cleanup masks the leak. Regression tests added in `test_kanban_db.py` cover both happy-path and exception-path closure, plus an explicit assertion that bare `with kb.connect()` still does NOT close (documenting the upstream sqlite3 behaviour we're working around). Closes #33159.