Initial commit: YouTube Shorts maker application

Features:
- Video download from TikTok/Douyin using yt-dlp
- Audio transcription with OpenAI Whisper
- GPT-4 translation (direct/summarize/rewrite modes)
- Subtitle generation with ASS format
- Video trimming with frame-accurate preview
- BGM integration with volume control
- Intro text overlay support
- Thumbnail generation with text overlay

Tech stack:
- Backend: FastAPI, Python 3.11+
- Frontend: React, Vite, TailwindCSS
- Video processing: FFmpeg
- AI: OpenAI Whisper, GPT-4

🤖 Generated with [Claude Code](https://claude.com/claude-code)

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

backend/requirements.txt

@@ -0,0 +1,14 @@
+fastapi>=0.109.0
+uvicorn[standard]>=0.27.0
+python-multipart>=0.0.6
+yt-dlp>=2024.10.7
+openai-whisper>=20231117
+openai>=1.12.0
+pydantic>=2.5.3
+pydantic-settings>=2.1.0
+aiofiles>=23.2.1
+python-jose[cryptography]>=3.3.0
+celery>=5.3.6
+redis>=5.0.1
+httpx>=0.26.0
+curl_cffi>=0.13.0,<0.14.0  # For yt-dlp browser impersonation (yt-dlp only supports <0.14)