[q6y6y6]

Summary

Add model-bound Qwen Image 2.1 Turbo INT8 Metal runtime support.

Changes

• Add the int8-metal MPS configuration for Qwen Image 2.1 Turbo.
• Add runtime validation for the model-bound Apple Metal dependency manifest.
• Validate model repository and revision metadata.
• Validate required K/N weight-shape coverage.
• Validate Metal library existence, size, and SHA-256 binding.
• Fail explicitly on missing or mismatched INT8 resources.
• Keep the existing BF16 and other quantization paths unchanged.
• Add focused tests for Qwen INT8 Metal binding validation.

Runtime Contract

The INT8 model must provide the matching apple_silicon_metal/ package and precompiled Metal libraries. The runtime must not silently fall back to BF16 when the INT8 Metal dependency is invalid.

Follow-up

After upstream merge, the runtime should be packaged and published as an official release artifact for the macOS App to consume.