feat(tui): add agent picker and agents list rpc

src/gateway/server-methods/agents.ts

@@ -0,0 +1,29 @@
+import { loadConfig } from "../../config/config.js";
+import {
+  ErrorCodes,
+  errorShape,
+  formatValidationErrors,
+  validateAgentsListParams,
+} from "../protocol/index.js";
+import { listAgentsForGateway } from "../session-utils.js";
+import type { GatewayRequestHandlers } from "./types.js";
+
+export const agentsHandlers: GatewayRequestHandlers = {
+  "agents.list": ({ params, respond }) => {
+    if (!validateAgentsListParams(params)) {
+      respond(
+        false,
+        undefined,
+        errorShape(
+          ErrorCodes.INVALID_REQUEST,
+          `invalid agents.list params: ${formatValidationErrors(validateAgentsListParams.errors)}`,
+        ),
+      );
+      return;
+    }
+
+    const cfg = loadConfig();
+    const result = listAgentsForGateway(cfg);
+    respond(true, result, undefined);
+  },
+};