Output tool via Arc<Mutex<Subconscious>> closure — complete

ToolHandler is now Arc<dyn Fn(...)> supporting closures that capture
state. The output tool is created during init_output_tool() as a
closure capturing Arc<Mutex<Subconscious>>, writing directly to
Subconscious.state. No more POC_AGENT_OUTPUT_DIR filesystem hack.

- All tool handlers wrapped in Arc::new()
- Tool is Clone (not Copy) — .copied() → .cloned()
- Subconscious wrapped in Arc<Mutex<>> on Mind
- Dead filesystem-based output() function removed
- memory_tools returns 11 items (output removed from static list)

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

src/agent/tools/mod.rs

@@ -143,7 +143,7 @@ pub async fn dispatch_with_agent(
     let tool = if let Some(ref a) = agent {
         // Only dispatch tools the agent is allowed to use
         let guard = a.state.lock().await;
-        guard.tools.iter().find(|t| t.name == name).copied()
+        guard.tools.iter().find(|t| t.name == name).cloned()
     } else {
         // No agent context — allow all tools (CLI/MCP path)
         tools().into_iter().find(|t| t.name == name)