Watch Together — synchronized clip sessions

• Watch Together: create/join password-protected rooms with unique codes
• Full playback sync (play, pause, seek, speed) over WebSocket
• Clip upload & streaming with chunked HTTP transfer and progress
• Shared random pool — server picks clips from any user's library
• Ready-sync protocol — everyone downloads before playback starts
• Host-only autoplay — no ping-pong desync between users
• Auto-reconnect with exponential backoff (5 attempts)
• Sync-on-join for late joiners
• Live ping/latency display, activity feed, connection status dot
• Host kick functionality
• Debug mode (--debug) with verbose logging
• Self-hosted server with Docker support (FastAPI + WebSocket)
• Server: bcrypt password hashing, rate limiting, room auto-expiry
• Code cleanup: removed unused imports, print() → logging"