chore: migrate backend from pip to uv

.gitignore

@@ -6,6 +6,7 @@ frontend/dist/
 
 # Python
 venv/
+.venv/
 __pycache__/
 *.pyc
 *.pyo

README.md

@@ -18,7 +18,7 @@ An open-source, local-first, Descript-like text-based audio and video editor pow
 ### Prerequisites
 
 - Node.js 18+
-- Python 3.10+
+- Python 3.11 ([uv](https://docs.astral.sh/uv/) handles the install automatically)
 - FFmpeg (in PATH)
 - (Optional) Ollama for local AI features
 
@@ -31,8 +31,8 @@ npm install
 # Frontend dependencies (React, Tailwind, Zustand)
 cd frontend && npm install && cd ..
 
-# Backend dependencies
-cd backend && pip install -r requirements.txt && cd ..
+# Backend dependencies (downloads Python 3.11, creates venv, installs deps)
+cd backend && uv sync && cd ..
 ```
 
 ### Run (Development)
@@ -46,7 +46,7 @@ Or run them separately:
 
 ```bash
 # Terminal 1: Backend
-cd backend && python -m uvicorn main:app --reload --port 8642
+cd backend && uv run uvicorn main:app --reload --port 8642
 
 # Terminal 2: Frontend
 cd frontend && npm run dev

backend/pyproject.toml

@@ -0,0 +1,45 @@
+[project]
+name = "cutscript-backend"
+version = "0.1.0"
+requires-python = "==3.11.*"
+dependencies = [
+    # FastAPI backend
+    "fastapi>=0.115.0",
+    "uvicorn[standard]>=0.32.0",
+    "websockets>=14.0",
+    "python-multipart>=0.0.12",
+
+    # Transcription (WhisperX for word-level alignment)
+    "whisperx>=3.1.0",
+    "faster-whisper>=1.0.0",
+
+    # Audio / Video processing
+    "moviepy>=1.0.3",
+    "ffmpeg-python>=0.2.0",
+    "soundfile>=0.10.3",
+
+    # ML / GPU
+    "torch>=2.0.0",
+    "torchaudio>=2.0.0",
+    # deepfilternet pins numpy<2.0 but only checks metadata; whisperx needs >=2.1 at runtime
+    "numpy>=2.1.0",
+
+    # Speaker diarization
+    "pyannote.audio>=3.1.1",
+
+    # AI providers
+    "openai>=1.50.0",
+    "anthropic>=0.39.0",
+    "requests>=2.28.0",
+
+    # Audio cleanup
+    "deepfilternet>=0.5.0",
+
+    # Utilities
+    "pydantic>=2.0.0",
+]
+
+[tool.uv]
+# deepfilternet declares numpy<2.0 but works fine at runtime with numpy 2.x.
+# whisperx requires numpy>=2.1, so override deepfilternet's stale constraint.
+override-dependencies = ["numpy>=2.1.0"]