Merge pull request #6637 from princeaden1/feat-xai-new-models

feat: new models for xAI (#6559)

Author: Leizhenpeng

app/constant.ts

@@ -673,6 +673,11 @@ const xAIModes = [
   "grok-3-beta",
   "grok-3",
   "grok-3-latest",
+  "grok-4",
+  "grok-4-0709",
+  "grok-4-fast-non-reasoning",
+  "grok-4-fast-reasoning",
+  "grok-code-fast-1",
 ];
 
 const chatglmModels = [