feat: auto select the first model as default model

frontend/src/core/models/hooks.ts

@@ -2,10 +2,11 @@ import { useQuery } from "@tanstack/react-query";
 
 import { loadModels } from "./api";
 
-export function useModels() {
+export function useModels({ enabled = true }: { enabled?: boolean } = {}) {
   const { data, isLoading, error } = useQuery({
     queryKey: ["models"],
     queryFn: () => loadModels(),
+    enabled,
   });
   return { models: data ?? [], isLoading, error };
 }

frontend/src/core/settings/local.ts

@@ -2,9 +2,9 @@ import type { AgentThreadContext } from "../threads";
 
 export const DEFAULT_LOCAL_SETTINGS: LocalSettings = {
   context: {
-    model_name: "deepseek-v3.2",
+    model_name: undefined,
     thinking_enabled: true,
-    is_plan_mode: false,
+    is_plan_mode: true,
   },
   layout: {
     sidebar_collapsed: false,

frontend/src/core/threads/types.ts

@@ -14,7 +14,7 @@ export interface AgentThread extends Thread<AgentThreadState> {}
 
 export interface AgentThreadContext extends Record<string, unknown> {
   thread_id: string;
-  model_name: string;
+  model_name: string | undefined;
   thinking_enabled: boolean;
   is_plan_mode: boolean;
 }