feat(llm): add new models for xAI and Google providers

Add 'grok-3-beta' to xAI provider and 'gemini-2.5-flash-preview-04-17' to Google provider. Also, ensure file saving when content is updated in WorkbenchStore and update streaming indicator styling in chat messages.

app/lib/stores/workbench.ts

@@ -513,6 +513,10 @@ export class WorkbenchStore {
 
       this.#editorStore.updateFile(fullPath, data.action.content);
 
+      if (!isStreaming && data.action.content) {
+        await this.saveFile(fullPath);
+      }
+
       if (!isStreaming) {
         await artifact.runner.runAction(data);
         this.resetAllFileModifications();