[Feature] Add real-time streaming dubbing mode

[Edmon02]

Summary

Add a streaming mode that can dub video in near-real-time chunks, enabling live dubbing use cases.

Tasks

• Implement chunked audio processing (stream ASR)
• Add WebSocket endpoint for real-time status/audio streaming
• Buffer management for translation context
• Low-latency TTS with streaming output
• Client-side player with dubbed audio overlay

Considerations

• Latency target: <3 second delay
• May need to skip lip-sync in streaming mode
• Requires smaller/faster model variants