feat: persistent whisper server + improved ComfyUI discovery

- Replace spawn-per-request with persistent whisper_server.py process
  that loads the model once (~170s) then transcribes in ~2s
- Add stdin/stdout JSON IPC protocol for whisper communication
- Recursive ComfyUI scan up to 4 levels deep (finds nested installs)
- Extract shared getPythonBin() to top-level (eliminates 3x duplication)
- Fix Ollama/ComfyUI spawn: shell:false + windowsHide:true (no extra
  console windows)
- Add loading state to transcribe-status endpoint

Co-Authored-By: Claude Opus 4.6 (1M context) <[email protected]>

Author: PurpleDoubleD

public/whisper_server.py

@@ -0,0 +1,88 @@
+"""
+Persistent faster-whisper server for Locally Uncensored.
+Communicates via stdin/stdout with line-based JSON protocol.
+
+Input (one JSON per line on stdin):
+  {"action": "transcribe", "path": "/tmp/audio.wav"}
+  {"action": "status"}
+  {"action": "quit"}
+
+Output (one JSON per line on stdout):
+  {"status": "ready", "backend": "faster-whisper"}
+  {"transcript": "hello world", "language": "en"}
+  {"error": "..."}
+"""
+
+import sys
+import json
+import os
+
+def main():
+    # Unbuffered stdout for real-time communication with Node.js
+    sys.stdout.reconfigure(line_buffering=True)
+    sys.stderr.reconfigure(line_buffering=True)
+
+    print("Loading faster-whisper model...", file=sys.stderr, flush=True)
+
+    try:
+        from faster_whisper import WhisperModel
+    except ImportError:
+        respond({"status": "error", "error": "faster-whisper not installed"})
+        sys.exit(1)
+
+    # Load model once — this is the slow part (~170s on some systems)
+    try:
+        model = WhisperModel("base", device="cpu", compute_type="int8")
+        print("Model loaded, ready for transcription.", file=sys.stderr, flush=True)
+    except Exception as e:
+        respond({"status": "error", "error": f"Model load failed: {e}"})
+        sys.exit(1)
+
+    # Signal readiness
+    respond({"status": "ready", "backend": "faster-whisper"})
+
+    # Main loop: read commands from stdin
+    for line in sys.stdin:
+        line = line.strip()
+        if not line:
+            continue
+
+        try:
+            cmd = json.loads(line)
+        except json.JSONDecodeError:
+            respond({"error": "Invalid JSON"})
+            continue
+
+        action = cmd.get("action", "")
+
+        if action == "status":
+            respond({"status": "ready", "backend": "faster-whisper"})
+
+        elif action == "transcribe":
+            audio_path = cmd.get("path", "")
+            if not audio_path or not os.path.exists(audio_path):
+                respond({"error": f"File not found: {audio_path}", "transcript": ""})
+                continue
+
+            try:
+                segments, info = model.transcribe(audio_path)
+                text = " ".join([s.text for s in segments]).strip()
+                respond({"transcript": text, "language": info.language})
+            except Exception as e:
+                respond({"error": str(e), "transcript": ""})
+
+        elif action == "quit":
+            respond({"status": "stopped"})
+            break
+
+        else:
+            respond({"error": f"Unknown action: {action}"})
+
+
+def respond(data: dict):
+    """Write a JSON response line to stdout."""
+    print(json.dumps(data), flush=True)
+
+
+if __name__ == "__main__":
+    main()