fix(agent-restrictions): add read-only restrictions for metis and momus

- Add metis and momus to AGENT_RESTRICTIONS with same pattern as oracle
- Deny write, edit, task, and delegate_task tools
- Enforces read-only design for these advisor agents
- Addresses cubic review feedback on #1462

Author: code-yeongyu

src/shared/agent-tool-restrictions.ts

@@ -24,6 +24,20 @@ const AGENT_RESTRICTIONS: Record<string, Record<string, boolean>> = {
     delegate_task: false,
   },
 
+  metis: {
+    write: false,
+    edit: false,
+    task: false,
+    delegate_task: false,
+  },
+
+  momus: {
+    write: false,
+    edit: false,
+    task: false,
+    delegate_task: false,
+  },
+
   "multimodal-looker": {
     read: true,
   },