fix(ui): responsive parent layout - remove max-w-4xl constraint

The job config page was capped at 896px (max-w-4xl), making the
10×4 translation preview table extremely squished. Changed to
max-w-full xl:max-w-7xl — full width on all screens, 1280px max
on ultrawide.

frontend/src/routes/translate/[id]/+page.svelte

@@ -593,7 +593,7 @@
   }
 </script>
 
-<div class="container mx-auto px-4 py-6 max-w-4xl">
+<div class="container mx-auto px-4 py-6 max-w-full xl:max-w-7xl">
   <!-- Header -->
   <div class="flex items-center justify-between mb-6">
     <div>