Fix type errors in turns and add to pyright checked set

Widen base strategy process_frame return types to ProcessFrameResult |
None to match actual behavior (None treated as CONTINUE). Give
UserTurnCompletionLLMServiceMixin a FrameProcessor base class so pyright
can see create_task, cancel_task, process_frame, and push_frame.

pyrightconfig.json

@@ -8,7 +8,8 @@
     "src/pipecat/transcriptions",
     "src/pipecat/frames",
     "src/pipecat/observers",
-    "src/pipecat/extensions"
+    "src/pipecat/extensions",
+    "src/pipecat/turns"
   ],
   "exclude": [
     "**/*_pb2.py",

src/pipecat/turns/user_start/base_user_turn_start_strategy.py

@@ -101,7 +101,7 @@ class BaseUserTurnStartStrategy(BaseObject):
         """Reset the strategy to its initial state."""
         pass
 
-    async def process_frame(self, frame: Frame) -> ProcessFrameResult:
+    async def process_frame(self, frame: Frame) -> ProcessFrameResult | None:
         """Process an incoming frame.
 
         Subclasses should override this to implement logic that decides whether
@@ -111,8 +111,8 @@ class BaseUserTurnStartStrategy(BaseObject):
             frame: The frame to be processed.
 
         Returns:
-            A ProcessFrameResult indicating the outcome. Subclasses that return
-            None are treated as CONTINUE for backward compatibility.
+            A ProcessFrameResult indicating the outcome, or None (treated as
+            CONTINUE for backward compatibility).
         """
         pass
 

src/pipecat/turns/user_stop/base_user_turn_stop_strategy.py

@@ -89,7 +89,7 @@ class BaseUserTurnStopStrategy(BaseObject):
         """Reset the strategy to its initial state."""
         pass
 
-    async def process_frame(self, frame: Frame) -> ProcessFrameResult:
+    async def process_frame(self, frame: Frame) -> ProcessFrameResult | None:
         """Process an incoming frame to decide whether the user stopped speaking.
 
         Subclasses should override this to implement logic that decides whether
@@ -99,8 +99,8 @@ class BaseUserTurnStopStrategy(BaseObject):
             frame: The frame to be analyzed.
 
         Returns:
-            A ProcessFrameResult indicating the outcome. Subclasses that return
-            None are treated as CONTINUE for backward compatibility.
+            A ProcessFrameResult indicating the outcome, or None (treated as
+            CONTINUE for backward compatibility).
         """
         pass
 

src/pipecat/turns/user_turn_completion_mixin.py

@@ -26,7 +26,7 @@ from pipecat.frames.frames import (
     LLMRunFrame,
     LLMTextFrame,
 )
-from pipecat.processors.frame_processor import FrameDirection
+from pipecat.processors.frame_processor import FrameDirection, FrameProcessor
 
 # Turn completion markers
 USER_TURN_COMPLETE_MARKER = "✓"
@@ -178,7 +178,7 @@ class UserTurnCompletionConfig:
         return self.incomplete_long_prompt or DEFAULT_INCOMPLETE_LONG_PROMPT
 
 
-class UserTurnCompletionLLMServiceMixin:
+class UserTurnCompletionLLMServiceMixin(FrameProcessor):
     """Mixin that adds turn completion detection to LLM services.
 
     This mixin provides methods to push LLM text with turn completion detection.