fix: preserve frame insertion order in BaseOutputTransport for equal PTS values

Frames sharing the same presentation timestamp were being reordered by the
priority queue. Adds a monotonic counter as a tiebreaker so frames with equal
PTS are always emitted in insertion order, preventing subtle audio/text
sequencing bugs.

src/pipecat/transports/base_output.py

@@ -448,6 +448,9 @@ class BaseOutputTransport(FrameProcessor):
             self._video_task: asyncio.Task | None = None
             self._clock_task: asyncio.Task | None = None
 
+            # If timestamps are equal, use this count to preserve the insertion order
+            self._clock_queue_counter = itertools.count()
+
         @property
         def sample_rate(self) -> int:
             """Get the audio sample rate.
@@ -498,7 +501,7 @@ class BaseOutputTransport(FrameProcessor):
                 frame: The end frame signaling sender shutdown.
             """
             # Let the sink tasks process the queue until they reach this EndFrame.
-            await self._clock_queue.put((float("inf"), frame.id, frame))
+            await self._clock_queue.put((float("inf"), next(self._clock_queue_counter), frame))
             await self._audio_queue.put(frame)
 
             # At this point we have enqueued an EndFrame and we need to wait for
@@ -610,7 +613,7 @@ class BaseOutputTransport(FrameProcessor):
             Args:
                 frame: The frame with timing information to handle.
             """
-            await self._clock_queue.put((frame.pts, frame.id, frame))
+            await self._clock_queue.put((frame.pts, next(self._clock_queue_counter), frame))
 
         async def handle_sync_frame(self, frame: Frame):
             """Handle frames that need synchronized processing.