feat: video-flow initial commit

- app.py: Streamlit UI for video generation workflow
- main_flow.py: CLI tool with argparse support
- modules/: Business logic modules (script_gen, image_gen, video_gen, composer, etc.)
- config.py: Configuration with API keys and paths
- requirements.txt: Python dependencies
- docs/: System prompt documentation

.gitignore

@@ -0,0 +1,56 @@
+# Environment
+.env
+.env.local
+.env.*.local
+
+# Python
+__pycache__/
+*.py[cod]
+*$py.class
+*.so
+.Python
+venv/
+ENV/
+*.egg-info/
+
+# Output
+output/
+*.mp4
+*.mp3
+*.wav
+*.m4a
+
+# Assets (downloaded)
+assets/fonts/*.ttf
+
+# IDE
+.idea/
+.vscode/
+*.swp
+*.swo
+
+# OS
+.DS_Store
+Thumbs.db
+
+# 参考
+参考/
+
+# 素材
+素材/
+
+# Images
+*.png
+*.jpeg
+*.jpg
+
+# Database & Logs
+*.db
+*.log
+
+# Temp files
+temp/
+
+# Binaries
+bin/
+