try to fix whisper issue

src/engine/stt.py

@@ -59,6 +59,7 @@ class WhisperEngine:
         """Lazy-load the Whisper model on first use."""
         if not self._model_loaded:
             models_dir = os.environ.get("WHISPER_MODELS_DIR")
+            model_path = os.path.join(models_dir, f"{self.model_name}.pt")
 
             # Check if models directory exists
             if not os.path.exists(models_dir):
@@ -66,8 +67,8 @@ class WhisperEngine:
                 raise RuntimeError(f"Models directory '{models_dir}' not found. Please create it first.")
 
             try:
-                logger.debug(f"Loading model '{self.model_name}' from {models_dir}")
-                self._model = whisper.load_model(self.model_name, download_root=models_dir, device=self.device)
+                logger.debug(f"Loading model '{self.model_name}' as from {model_path}")
+                self._model = whisper.load_model(model_path, device=self.device)
                 self._model_loaded = True
                 logger.debug(f"Successfully loaded model '{self.model_name}' on {self.device}")
             except Exception as e: