drop python backend layer

README.md

@@ -6,51 +6,34 @@ Keyboard sounds are sourced from [kbsim](https://github.com/tplai/kbsim) (MIT li
 
 ## Requirements
 
-- [uv](https://docs.astral.sh/uv/) (Python package manager)
 - Node.js 18+ and npm
-- **ffmpeg** on your PATH (required by pydub for audio export)
 - **git** (to fetch kbsim sample assets)
 
-```bash
-# macOS
-brew install ffmpeg
-```
-
 ## Setup
 
 ```bash
-# Python dependencies
-uv sync
-
 # Frontend dependencies
 cd frontend && npm install
 
 # Download kbsim switch samples (~151 MP3 files)
-./scripts/fetch_kbsim_samples.sh
+cd .. && ./scripts/fetch_kbsim_samples.sh
 ```
 
 ## Development
 
-Run both servers in separate terminals:
-
 ```bash
-# Terminal 1 — FastAPI backend (audio export API)
-uv run uvicorn backend.main:app --reload
-
-# Terminal 2 — Vite dev server (proxies /api to :8000)
 cd frontend && npm run dev
 ```
 
 Open http://localhost:5173
 
-## Production-like run
+## Production
 
 ```bash
-cd frontend && npm run build
-uv run uvicorn backend.main:app --host 127.0.0.1 --port 8000
+cd frontend && npm run build && npm run preview
 ```
 
-Open http://127.0.0.1:8000
+Or serve `frontend/dist` with any static file host.
 
 ## Usage
 
@@ -60,8 +43,9 @@ Open http://127.0.0.1:8000
    - Each physical key maps to a stable press variant (same key always sounds the same)
 3. Select markers to override keys, nudge with arrow keys, or multi-select with marquee drag
 4. Choose a mechanical switch sound from the dropdown (13 kbsim profiles)
-5. **Save Project** / **Open Project** — JSON with version, markers, and switch setting (no video path)
-6. **Export Audio** — download a WAV file of keyboard sounds only, full video length
+5. Adjust preview speed (25–200%) for fast-paced content — preview only; export is always at 1×
+6. **Save Project** / **Open Project** — JSON with version, markers, and switch setting (no video path)
+7. **Export Audio** — download a WAV file of keyboard sounds only, full video length (rendered client-side)
 
 ### Keyboard shortcuts
 
@@ -107,4 +91,4 @@ Keyboard sound samples from [tplai/kbsim](https://github.com/tplai/kbsim) by Tho
 
 - Frame stepping uses `video.currentTime` and may land on nearest keyframes for some MP4 encodings
 - Project files do not reference the video file path
-- Very long videos may take longer to export via pydub in-memory overlay
+- Very long videos may take longer to export client-side via OfflineAudioContext