[本地语音降噪]：完成本地语音链路和噪音过滤，包含降噪模型、本地ASR和实时字幕稳定策略

src/owner_voice_pet/protocols.py

@@ -49,6 +49,20 @@ class WakeWordProvider(Protocol):
         ...
 
 
+class AudioPreprocessor(Protocol):
+    def load(self) -> None:
+        ...
+
+    def reset(self) -> None:
+        ...
+
+    def process_frame(self, frame: AudioFrame) -> AudioFrame:
+        ...
+
+    def flush(self) -> list[AudioFrame]:
+        ...
+
+
 class VadProvider(Protocol):
     def load(self) -> None:
         ...