```

feat(cli): add direct model inference via new run subcommand

- Add `aha run` CLI subcommand for direct model inference without HTTP service
- Support multiple models including Qwen series, OCR models, ASR models, and voice generation
- Implement input/output handling with file path support and auto-generation
- Add comprehensive documentation in CLI_USAGE.md with examples
- Include performance timing for model loading and inference operations
- Add macOS build target to Makefile with Metal support
```

src/lib.rs

@@ -1,4 +1,5 @@
 pub mod chat_template;
+pub mod exec;
 pub mod models;
 pub mod position_embed;
 pub mod tokenizer;