fix(workflow): track fixed speech at transport output

backend/services/fixed_speech.py

@@ -3,14 +3,17 @@
 from __future__ import annotations
 
 from collections.abc import Awaitable
-from typing import Any
+from typing import TYPE_CHECKING, Any
 
 from pipecat.frames.frames import OutputTransportMessageUrgentFrame, TTSSpeakFrame
 from pipecat.utils.time import time_now_iso8601
 
-from services.brains.base import BrainRuntime
+from services.pipecat.call_lifecycle import playback_marker_for
 from services.runtime_variables import DynamicVariableStore
 
+if TYPE_CHECKING:
+    from services.brains.base import BrainRuntime
+
 
 FIXED_SPEECH_CONTEXT_MARKER = "[会话事实：以下固定消息已向用户播报]"
 
@@ -79,6 +82,10 @@ class FixedSpeechOutput:
         await self._runtime.queue_frame(
             TTSSpeakFrame(content, append_to_context=False)
         )
+        playback_marker = playback_marker_for(playback_completion)
+        if playback_marker is not None:
+            await self._runtime.queue_frame(playback_marker)
+            playback_marker.completion.mark_queued()
         return playback_completion
 
     async def emit(self, message: dict[str, Any]) -> None: