WIP: Output tool via Arc<Mutex<Subconscious>>, ToolHandler to Arc<dyn Fn>

- ToolHandler changed to Arc<dyn Fn(...)> (supports closures)
- Subconscious wrapped in Arc<Mutex<>> on Mind
- init_output_tool() pushes output tool closure capturing the Arc
- Output removed from static memory_tools()
- Most tool handlers wrapped in Arc::new() but some have paren issues

Co-Authored-By: Proof of Concept <poc@bcachefs.org>

src/agent/tools/vision.rs

@@ -23,7 +23,7 @@ pub fn tool() -> super::Tool {
         name: "view_image",
         description: "View an image file or capture a tmux pane screenshot. Supports PNG, JPEG, GIF, WebP. Use pane_id to capture a tmux pane instead.",
         parameters_json: r#"{"type":"object","properties":{"file_path":{"type":"string","description":"Path to an image file"},"pane_id":{"type":"string","description":"Tmux pane ID to capture (e.g. '0:1.0')"},"lines":{"type":"integer","description":"Lines to capture from tmux pane (default 50)"}}}"#,
-        handler: |_a, v| Box::pin(async move { view_image_text(&v) }),
+        handler: Arc::new(|_a, v| Box::pin(async move { view_image_text(&v)) }),
     }
 }