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/app/services/__init__.py

@@ -0,0 +1,15 @@
+from app.services.downloader import download_video, detect_platform, get_video_info
+from app.services.transcriber import transcribe_video, segments_to_srt, segments_to_ass
+from app.services.translator import (
+    translate_segments,
+    translate_single,
+    generate_shorts_script,
+    TranslationMode,
+)
+from app.services.video_processor import (
+    process_video,
+    get_video_duration,
+    extract_audio,
+    extract_audio_with_noise_reduction,
+    analyze_audio_noise_level,
+)