feat(transcription): expose onnx model_dir for the dispatcher (T3.4)

src-tauri/src/transcription/onnx_models.rs

@@ -34,6 +34,12 @@ fn onnx_dir(id: &str) -> PathBuf {
     models_dir().join("onnx-whisper").join(id)
 }
 
+/// Directory holding a model's ONNX artifacts — what `OnnxNpuTranscriber::load`
+/// expects as its `model` path.
+pub fn model_dir(id: &str) -> PathBuf {
+    onnx_dir(id)
+}
+
 /// Local paths for the given model id (whether or not they exist yet).
 pub fn model_files(id: &str) -> OnnxModelFiles {
     let dir = onnx_dir(id);