Add text features: trusted triggers, context cache, response policy, MCP config tools

poc/src/core-client.ts

@@ -131,6 +131,10 @@ export class CoreClient {
         return this.request("message.read", { channelId, limit });
     }
 
+    async fetchMessages(channelId: string, limit: number, options: { before?: string; after?: string } = {}) {
+        return this.request("message.fetch", { channelId, limit, ...options });
+    }
+
     close() {
         this.socket.destroy();
     }