feat: Support a way to define default model by adding DEFAULT_MODEL env.

app/utils/hooks.ts

@@ -1,14 +1,15 @@
 import { useMemo } from "react";
 import { useAccessStore, useAppConfig } from "../store";
-import { collectModels } from "./model";
+import { collectModels, collectModelsWithDefaultModel } from "./model";
 
 export function useAllModels() {
   const accessStore = useAccessStore();
   const configStore = useAppConfig();
   const models = useMemo(() => {
-    return collectModels(
+    return collectModelsWithDefaultModel(
       configStore.models,
       [configStore.customModels, accessStore.customModels].join(","),
+      accessStore.defaultModel,
     );
   }, [accessStore.customModels, configStore.customModels, configStore.models]);