fix: silent memory flush failure on /new and /resume commands

The _async_flush_memories() helper accepts (session_id) but both the
/new and /resume handlers passed two arguments (session_id, session_key).
The TypeError was silently swallowed at DEBUG level, so memory extraction
never ran when users typed /new or /resume.

One call site (the session expiry watcher) was already fixed in 9c96f669,
but /new and /resume were missed.

- gateway/run.py:3247 — remove stray session_key from /new handler
- gateway/run.py:4989 — remove stray session_key from /resume handler
- tests/gateway/test_resume_command.py:222 — update test assertion

gateway/run.py

@@ -3244,7 +3244,7 @@ class GatewayRunner:
             old_entry = self.session_store._entries.get(session_key)
             if old_entry:
                 _flush_task = asyncio.create_task(
-                    self._async_flush_memories(old_entry.session_id, session_key)
+                    self._async_flush_memories(old_entry.session_id)
                 )
                 self._background_tasks.add(_flush_task)
                 _flush_task.add_done_callback(self._background_tasks.discard)
@@ -4990,7 +4990,7 @@ class GatewayRunner:
         # Flush memories for current session before switching
         try:
             _flush_task = asyncio.create_task(
-                self._async_flush_memories(current_entry.session_id, session_key)
+                self._async_flush_memories(current_entry.session_id)
             )
             self._background_tasks.add(_flush_task)
             _flush_task.add_done_callback(self._background_tasks.discard)

tests/gateway/test_resume_command.py

@@ -201,8 +201,8 @@ class TestHandleResumeCommand:
         db.close()
 
     @pytest.mark.asyncio
-    async def test_resume_flushes_memories_with_gateway_session_key(self, tmp_path):
-        """Resume should preserve the gateway session key for Honcho flushes."""
+    async def test_resume_flushes_memories(self, tmp_path):
+        """Resume should flush memories from the current session before switching."""
         from hermes_state import SessionDB
 
         db = SessionDB(db_path=tmp_path / "state.db")
@@ -221,6 +221,5 @@ class TestHandleResumeCommand:
 
         runner._async_flush_memories.assert_called_once_with(
             "current_session_001",
-            _session_key_for_event(event),
         )
         db.close()