Add timestamp frames and include timestamps in the transcription event and frame

src/pipecat/frames/frames.py

@@ -207,6 +207,20 @@ class InterimTranscriptionFrame(TextFrame):
         return f"{self.name}(user: {self.user_id}, text: [{self.text}], language: {self.language}, timestamp: {self.timestamp})"
 
 
+@dataclass
+class OpenAILLMContextUserTimestampFrame(DataFrame):
+    """Timestamp information for user message in LLM context."""
+
+    timestamp: str
+
+
+@dataclass
+class OpenAILLMContextAssistantTimestampFrame(DataFrame):
+    """Timestamp information for assistant message in LLM context."""
+
+    timestamp: str
+
+
 @dataclass
 class TranscriptionMessage:
     """A message in a conversation transcript containing the role and content.