fix: change PushSubscription endpoint to VARCHAR for MySQL compatibility

MySQL cannot create unique constraints on TEXT fields without length.
Changed endpoint from @db.Text to @db.VarChar(512) to fix Prisma generation error.

.gitignore

@@ -23,7 +23,7 @@ yarn-debug.log*
 yarn-error.log*
 
 # Local env files
-.env
+# .env
 .env*.local
 
 # Vercel