Phase 2: Core transcription pipeline and audio playback

- Implement faster-whisper TranscribeService with word-level timestamps,
  progress reporting, and hardware auto-detection
- Wire up Rust SidecarManager for Python process lifecycle (spawn, IPC, shutdown)
- Add transcribe_file Tauri command bridging frontend to Python sidecar
- Integrate wavesurfer.js WaveformPlayer with play/pause, skip, seek controls
- Build TranscriptEditor with word-level click-to-seek and active highlighting
- Connect file import flow: prompt → asset load → transcribe → display
- Add typed tauri-bridge service with TranscriptionResult interface
- Add Python tests for hardware detection and transcription result formatting

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

python/voice_to_notes/ipc/handlers.py

@@ -37,3 +37,49 @@ class HandlerRegistry:
 def ping_handler(msg: IPCMessage) -> IPCMessage:
     """Simple ping handler for testing connectivity."""
     return IPCMessage(id=msg.id, type="pong", payload={"echo": msg.payload})
+
+
+def make_transcribe_handler() -> HandlerFunc:
+    """Create a transcription handler with a persistent TranscribeService."""
+    from voice_to_notes.services.transcribe import TranscribeService, result_to_payload
+
+    service = TranscribeService()
+
+    def handler(msg: IPCMessage) -> IPCMessage:
+        payload = msg.payload
+        result = service.transcribe(
+            request_id=msg.id,
+            file_path=payload["file"],
+            model_name=payload.get("model", "base"),
+            device=payload.get("device", "cpu"),
+            compute_type=payload.get("compute_type", "int8"),
+            language=payload.get("language"),
+        )
+        return IPCMessage(
+            id=msg.id,
+            type="transcribe.result",
+            payload=result_to_payload(result),
+        )
+
+    return handler
+
+
+def hardware_detect_handler(msg: IPCMessage) -> IPCMessage:
+    """Detect hardware capabilities and return recommendations."""
+    from voice_to_notes.hardware.detect import detect_hardware
+
+    info = detect_hardware()
+    return IPCMessage(
+        id=msg.id,
+        type="hardware.info",
+        payload={
+            "has_cuda": info.has_cuda,
+            "cuda_device_name": info.cuda_device_name,
+            "vram_mb": info.vram_mb,
+            "ram_mb": info.ram_mb,
+            "cpu_cores": info.cpu_cores,
+            "recommended_model": info.recommended_model,
+            "recommended_device": info.recommended_device,
+            "recommended_compute_type": info.recommended_compute_type,
+        },
+    )