[唤醒应答与快速端点]：完成唤醒后我在播报和本地VAD端点优化，包含缓冲清理、配置项和测试覆盖

tests/test_transport.py

@@ -42,6 +42,12 @@ class TransportTests(unittest.TestCase):
         self.assertFalse(result.played)
         self.assertEqual(result.error.code, ErrorCode.AUDIO_OUTPUT_DEVICE_MISSING)
 
+    def test_memory_transport_flushes_input_frames(self) -> None:
+        transport = MemoryAudioTransport([frame(1, 0), frame(2, 20)])
+        transport.start_input()
+        self.assertEqual(transport.flush_input(), 2)
+        self.assertEqual(transport.read_frames(10), [])
+
     def test_file_replay_roundtrip(self) -> None:
         frames = [frame(1, 0, {"wake": True}), frame(2, 20, {"speech": True})]
         with tempfile.TemporaryDirectory() as tmp:
@@ -76,6 +82,14 @@ class TransportTests(unittest.TestCase):
         self.assertEqual(frames[0].pcm, b"\x01\x00\x02\x00")
         self.assertEqual(frames[0].sample_rate, 16000)
 
+    def test_sounddevice_transport_flushes_queued_input(self) -> None:
+        fake = FakeSoundDevice()
+        transport = SoundDeviceAudioTransport(sounddevice_module=fake)
+        transport.start_input(sample_rate=16000, channels=1)
+        self.assertEqual(transport.flush_input(), 1)
+        self.assertEqual(transport.read_frames(0), [])
+        transport.stop()
+
     def test_sounddevice_transport_plays_pcm_to_raw_output_stream(self) -> None:
         fake = FakeSoundDevice()
         transport = SoundDeviceAudioTransport(sounddevice_module=fake)