Part of issue

#3057

What does this PR do?

Implement snac features and integration

Summary

• Implement SNAC (Multi-Scale Neural Audio Codec) integration for
  Text-to-Speech applications
• Add comprehensive TTS utilities and configuration presets for speech
  synthesis
• Provide example demonstrating Qwen + SNAC TTS pipeline

Changes Made

• New module: snac_tts_integration.rs with TTS-optimized SNAC codec
  wrapper
• Enhanced SNAC model: Added TTS-specific methods (encode_for_tts,
  decode_from_tts_tokens, batch processing)
• Config presets: Added default_tts(), high_quality_tts(), fast_tts()
  configurations
• Utility functions: Memory estimation, token validation, voice embedding
  creation
• Example implementation: qwen_snac_tts_example.rs showing complete TTS
  pipeline

Key Features

• Multiple quality presets: 24kHz speech, 32kHz general, fast 16kHz
  options
• TTS pipeline abstraction: SnacTtsPipeline for easy integration with
  language models
• Batch processing support: Efficient handling of multiple audio streams
• Memory optimization: Token padding, truncation, and memory estimation
  utilities
• Voice cloning support: Reference audio embedding extraction