Fix asr boundary bug

engine/app/config.py

@@ -53,6 +53,14 @@ class Settings(BaseSettings):
     siliconflow_asr_model: str = Field(default="FunAudioLLM/SenseVoiceSmall", description="SiliconFlow ASR model")
     asr_interim_interval_ms: int = Field(default=500, description="Interval for interim ASR results in ms")
     asr_min_audio_ms: int = Field(default=300, description="Minimum audio duration before first ASR result")
+    asr_pre_speech_ms: int = Field(
+        default=240,
+        description="Audio context (ms) prepended before detected speech to avoid clipping first phoneme"
+    )
+    asr_final_tail_ms: int = Field(
+        default=120,
+        description="Silence tail (ms) appended before final ASR decode to protect utterance ending"
+    )
     
     # Duplex Pipeline Configuration
     duplex_enabled: bool = Field(default=True, description="Enable duplex voice pipeline")