tools: each module owns its Tool list, no duplication

Each tool module exports its own tools() returning Vec<Tool>.
mod.rs::tools() chains them. Individual _def() and handler functions
are pub(super), not exported. Aggregate definitions derived from
the Tool lists.

- memory: memory_tools(), journal_tools()
- channels: tools()
- control: tools()
- mod.rs: just chains + adds file/bash/web/vision

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

src/agent/tools/channels.rs

@@ -51,7 +51,16 @@ pub fn definitions() -> Vec<ToolDef> {
     ]
 }
 
-// ── Dispatch ───────────────────────────────────────────────────
+pub fn tools() -> Vec<super::Tool> {
+    use super::Tool;
+    let defs = definitions();
+    vec![
+        Tool { def: defs[0].clone(), handler: |_a, _v| Box::pin(async move { channel_list().await }) },
+        Tool { def: defs[1].clone(), handler: |_a, v| Box::pin(async move { channel_recv(&v).await }) },
+        Tool { def: defs[2].clone(), handler: |_a, v| Box::pin(async move { channel_send(&v).await }) },
+        Tool { def: defs[3].clone(), handler: |_a, _v| Box::pin(async move { channel_notifications().await }) },
+    ]
+}
 
 // ── Tool implementations ───────────────────────────────────────