feat: add node binding controls in control ui

docs/tools/exec.md

@@ -48,6 +48,8 @@ clawdbot config get agents.list
 clawdbot config set agents.list[0].tools.exec.node "node-id-or-name"
 ```
 
+Control UI: the Nodes tab includes a small “Exec node binding” panel for the same settings.
+
 ## Session overrides (`/exec`)
 
 Use `/exec` to set **per-session** defaults for `host`, `security`, `ask`, and `node`.