```

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/exec/mod.rs

@@ -0,0 +1,37 @@
+//! CLI exec module for direct model inference
+//!
+//! This module provides model-specific exec implementations for the `run` subcommand.
+//! Each model has its own exec module that handles input/output parsing and model invocation.
+
+pub mod deepseek_ocr;
+pub mod fun_asr_nano;
+pub mod glm_asr_nano;
+pub mod hunyuan_ocr;
+pub mod minicpm4;
+pub mod paddleocr_vl;
+pub mod qwen2_5vl;
+pub mod qwen3;
+pub mod qwen3vl;
+pub mod rmbg2_0;
+pub mod voxcpm;
+pub mod voxcpm1_5;
+
+use anyhow::Result;
+
+/// Trait for model exec implementations
+///
+/// Each model exec module implements this trait to provide
+/// model-specific inference logic for CLI `run` commands.
+pub trait ExecModel {
+    /// Run inference with the given input and output parameters
+    ///
+    /// # Arguments
+    /// * `input` - Input text or file path (interpretation is model-specific)
+    /// * `output` - Optional output file path (if None, model will auto-generate)
+    /// * `weight_path` - Path to the model weights
+    ///
+    /// # Returns
+    /// * `Ok(())` on success
+    /// * `Err(anyhow::Error)` on failure
+    fn run(input: &str, output: Option<&str>, weight_path: &str) -> Result<()>;
+}