Unify TUI slash commands and harden tool inventory responses

src/backends/native/agent.ts

@@ -567,6 +567,16 @@ export class NativeAgent {
     };
   }
 
+  getAvailableToolNames(): string[] {
+    if (!this.toolRegistry) {
+      return [];
+    }
+    return this.toolRegistry
+      .filteredList(this._toolPolicyContext)
+      .map((tool) => tool.name)
+      .sort();
+  }
+
   setAttachmentCollector(collector: OutboundAttachmentCollector | undefined): void {
     this._attachmentCollector = collector;
   }