fix: remove 115 verified dead code symbols across 46 production files

Automated dead code audit using vulture + coverage.py + ast-grep intersection,
confirmed by Opus deep verification pass. Every symbol verified to have zero
production callers (test imports excluded from reachability analysis).

Removes ~1,534 lines of dead production code across 46 files and ~1,382 lines
of stale test code. 3 entire files deleted (agent/builtin_memory_provider.py,
hermes_cli/checklist.py, tests/hermes_cli/test_setup_model_selection.py).

Co-authored-by: alt-glitch <balyan.sid@gmail.com>

tools/browser_camofox.py

@@ -589,25 +589,4 @@ def camofox_console(clear: bool = False, task_id: Optional[str] = None) -> str:
     })
 
 
-# ---------------------------------------------------------------------------
-# Cleanup
-# ---------------------------------------------------------------------------
 
-def cleanup_all_camofox_sessions() -> None:
-    """Close all active camofox sessions.
-
-    When managed persistence is enabled, only clears local tracking state
-    without destroying server-side browser profiles (cookies, logins, etc.
-    must survive).  Ephemeral sessions are fully deleted on the server.
-    """
-    managed = _managed_persistence_enabled()
-    with _sessions_lock:
-        sessions = list(_sessions.items())
-    if not managed:
-        for _task_id, session in sessions:
-            try:
-                _delete(f"/sessions/{session['user_id']}")
-            except Exception:
-                pass
-    with _sessions_lock:
-        _sessions.clear()