Can I vibecode Subclip?

Build me the closest honest personal substitute for Subclip, not a platform clone. Requirements:

- Use Python 3.12 + FastAPI for a localhost web app, with a plain JavaScript frontend,
  FFmpeg for media work, and faster-whisper for word-level transcription.
- I can import MP4, MOV, WebM, MP3, or WAV files, see a synced transcript beside the
  video preview, and click any word to seek to its timestamp.
- Deleting transcript ranges creates an undoable cut list. Detect silences longer than
  500 ms and let me accept or reject each suggested cut before rendering.
- Let me edit subtitle text and timing, import or export SRT, and apply one ASS style
  file with font, colors, outline, position, and words-per-line controls.
- Export MP4 in 16:9, 9:16, or 1:1 with center-crop or blur-pad. Never overwrite the
  source, and show FFmpeg progress plus a useful failure message.
- Store projects as JSON under ~/SubclipDIY/projects and renders under
  ~/SubclipDIY/exports, with a recent-projects page and a delete-project action.
- Bind to localhost only. No accounts, uploads, telemetry, or network calls after the
  faster-whisper model has been downloaded.
- Deliberately exclude ONNX models in the browser, Remotion client or server rendering,
  native apps, cloud dubbing, render queues, publishing, an MCP server, and public APIs.
- Add unit tests for cut-list merging and subtitle grouping, plus one smoke test that
  imports a short fixture and produces a playable MP4.
- Include a README with setup for Python and FFmpeg, model-size guidance, data paths,
  supported formats, and an honest warning about CPU transcription and render speed.