feat: implement OpenAI-compatible Realtime API with authentication and management features

- Added support for public Realtime API, including new routes for managing API keys and handling WebRTC connections.
- Introduced RealtimeApiKey model and associated CRUD operations for admin management of API keys.
- Implemented authentication mechanisms for API keys and client secrets.
- Enhanced environment configuration with new secrets for Realtime API.
- Created OpenAIRealtime session management and event processing for real-time interactions.
- Updated schemas and settings to accommodate new features and ensure compatibility with existing systems.

backend/services/pipecat/turn_config.py

@@ -20,7 +20,10 @@ from pipecat.turns.user_stop import (
     SpeechTimeoutUserTurnStopStrategy,
     TurnAnalyzerUserTurnStopStrategy,
 )
-from pipecat.turns.user_turn_strategies import UserTurnStrategies
+from pipecat.turns.user_turn_strategies import (
+    ExternalUserTurnStrategies,
+    UserTurnStrategies,
+)
 
 
 DEFAULT_VAD = {
@@ -126,3 +129,13 @@ class ConfigurableLLMUserAggregator(LLMUserAggregator):
             enable_interruptions=enable_interruptions,
         )
         await self._user_turn_controller.update_strategies(strategies)
+
+    async def apply_external_turn_control(self, enabled: bool) -> None:
+        """Switch between client-controlled PTT and the configured VAD."""
+
+        strategies = (
+            ExternalUserTurnStrategies()
+            if enabled
+            else self._params.user_turn_strategies
+        )
+        await self._user_turn_controller.update_strategies(strategies)