Implement Local Models for TTS and STT Services

[shubhh139]

TTS and STT endpoints only support external AI4Bharat APIs. Implement local models similar to the IndicTrans2 translation service for better performance, privacy, and offline capability.

Acceptance Criteria

• Research and implement local TTS model (e.g., IndicTTS, Coqui TTS, or similar)
• Research and implement local STT model (e.g., IndicWav2Vec, Whisper, or similar)
• Add environment variables for local model configuration
• Implement dual-mode support (local vs external API)
• Add model loading and caching mechanisms
• Update documentation with local model setup instructions

Estimation: 24 hours