fix(gateway): /loop paths warm the SessionDB cache off-loop

The loops delegation (previous commit) moved /loop onto the shared
bootstrap windows, but the loop-class gateway callers still constructed
LoopManager on the loop thread with no warm-up — the same false-ack
class as /goal, one sibling over:

- The /loop command handler: a cold init past the window made
  save_loop discard the write while the reply claimed the loop was
  set. Reproduced with a 2s init: "↻ Loop set" with nothing persisted;
  with the warm-up the loop persists.
- _post_turn_loop_completion: a cold cache at the turn boundary
  stalled the loop for the init duration and could drop the
  tick-completion write.
- _loop_wakeup_watcher: the scan reads every persisted loop, so a cold
  cache ran the state.db init on the loop thread before the first
  read.

All three now warm the cache off-loop first (same helper, same reason
as the goal paths). save_loop also logs at WARNING when it drops a
write, matching save_goal: the reply has already told the user the
loop was set.

Review findings (PR #88965): the goal and heartbeat command paths
warmed off-loop, the loop-class paths did not.

gateway/run.py

@@ -21397,6 +21397,12 @@ class GatewayRunner(GatewayAuthorizationMixin, GatewayKanbanWatchersMixin, Gatew
         if not sid:
             return
 
+        # Warm the SessionDB cache off-loop. A cold cache at the turn
+        # boundary stalls the loop for the init duration and can drop
+        # the tick-completion write (the /goal continuation seam, one
+        # sibling over).
+        await self._warm_goals_session_db("loop completion")
+
         mgr = LoopManager(session_id=sid)
         state = mgr.state
         if state is None or not state.awaiting_response:
@@ -21435,6 +21441,11 @@ class GatewayRunner(GatewayAuthorizationMixin, GatewayKanbanWatchersMixin, Gatew
                     list_active_loops,
                 )
 
+                # Warm the cache off-loop once per scan. The scan reads
+                # every persisted loop, so a cold cache runs the state.db
+                # init on the loop thread before the first read.
+                await self._warm_goals_session_db("loop wakeup")
+
                 now = time.time()
                 for sid, state in list_active_loops():
                     if state.awaiting_response or now < state.next_due_at:

gateway/slash_commands.py

@@ -3038,6 +3038,10 @@ class GatewaySlashCommandsMixin:
         except Exception as exc:
             logger.debug("loop manager unavailable: %s", exc)
             return None, None
+        # Warm the SessionDB cache off-loop. A cold cache drops the first
+        # /loop write while the reply claims the loop was set (same class
+        # as the /goal false-ack fix).
+        await self._warm_goals_session_db("loop manager")
         try:
             session_entry = await self.async_session_store.get_or_create_session(event.source)
         except Exception:

hermes_cli/loops.py

@@ -415,6 +415,12 @@ def save_loop(session_id: str, state: LoopState) -> None:
         return
     db = _get_session_db()
     if db is None:
+        logger.warning(
+            "LoopManager: loop for %s not persisted — session DB "
+            "unavailable (bootstrap window exceeded, in-memory state "
+            "still active)",
+            session_id,
+        )
         return
     try:
         db.set_meta(_meta_key(session_id), state.to_json())