Adds bitsandbytes 8-bit quantization on the main LM as an alternative
memory-saving path. The audio_tokenizer (where fp16 broke output
quality) stays fp32 and is unaffected.
Wiring:
- New "int8" entry in MOSSTTSLoader's dtype dropdown
- get_or_load branches on dtype_str == "int8" — passes BitsAndBytesConfig
+ device_map={"": resolved_device} to from_pretrained, skipping the
torch_dtype + .to(device) path (incompatible with bnb-loaded models)
- bitsandbytes is lazy-imported with a clear install message; only int8
users pay the dependency
- Validates that int8 is requested only on cuda (no cpu kernels)
Co-Authored-By: Claude Opus 4.7 <noreply@anthropic.com>
