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/config.py

@@ -0,0 +1,53 @@
+from pydantic_settings import BaseSettings
+from functools import lru_cache
+
+
+class Settings(BaseSettings):
+    # API Keys
+    OPENAI_API_KEY: str = ""
+    PIXABAY_API_KEY: str = ""  # Optional: for Pixabay music search
+    FREESOUND_API_KEY: str = ""  # Optional: for Freesound API (https://freesound.org/apiv2/apply)
+
+    # Directories
+    DOWNLOAD_DIR: str = "data/downloads"
+    PROCESSED_DIR: str = "data/processed"
+    BGM_DIR: str = "data/bgm"
+
+    # Whisper settings
+    WHISPER_MODEL: str = "medium"  # small, medium, large
+
+    # Redis
+    REDIS_URL: str = "redis://redis:6379/0"
+
+    # OpenAI settings
+    OPENAI_MODEL: str = "gpt-4o-mini"  # gpt-4o-mini, gpt-4o, gpt-4-turbo
+    TRANSLATION_MAX_TOKENS: int = 1000  # Max tokens for translation (cost control)
+    TRANSLATION_MODE: str = "rewrite"  # direct, summarize, rewrite
+
+    # GPT Prompt Customization
+    GPT_ROLE: str = "친근한 유튜브 쇼츠 자막 작가"  # GPT persona/role
+    GPT_TONE: str = "존댓말"  # 존댓말, 반말, 격식체
+    GPT_STYLE: str = ""  # Additional style instructions (optional)
+
+    # Processing
+    DEFAULT_FONT_SIZE: int = 24
+    DEFAULT_FONT_COLOR: str = "white"
+    DEFAULT_BGM_VOLUME: float = 0.3
+
+    # Server
+    PORT: int = 3000  # Frontend port
+
+    # Proxy (for geo-restricted platforms like Douyin)
+    PROXY_URL: str = ""  # http://host:port or socks5://host:port
+
+    class Config:
+        env_file = "../.env"  # Project root .env file
+        extra = "ignore"  # Ignore extra fields in .env
+
+
+@lru_cache()
+def get_settings():
+    return Settings()
+
+
+settings = get_settings()