Fix critical template parameter error causing build failures

- Fix template passing in page.tsx to always use full templates object
- Add null safety check in templates.ts to prevent undefined lib property access
- Remove unused currentTemplate variable

This resolves the 'Cannot read properties of undefined (reading join)' error
that was preventing successful builds and message submissions.

Author: Gerome El-assaad

app/api/sandbox/route.ts

@@ -80,7 +80,6 @@ export async function POST(req: Request) {
         await Promise.all(fragment.code.map(async (file) => {
           await sbx.files.write(file.file_path, file.file_content)
         }))
-      } else {
       } else if (fragment.code !== null && fragment.code !== undefined) {
         await sbx.files.write(fragment.file_path, fragment.code)
       } else {

app/page.tsx

@@ -278,7 +278,7 @@ export default function Home() {
       userID: session?.user?.id,
       teamID: userTeam?.id,
       messages: toAISDKMessages(updatedMessages),
-      template: templates[selectedTemplate],
+      template: templates,
       model: currentModel,
       config: languageModel,
     })

hooks/use-enhanced-chat.ts

@@ -109,10 +109,6 @@ export function useEnhancedChat(chatConfig: EnhancedChatConfig) {
 
         trackError(error.message)
         throw error
-      } finally {
-        if (retryCount > 0) {
-          setIsSubmitting(false)
-        }
       } finally {
         setIsSubmitting(false)
       }