Tighten ultrawide layout with visible side gutters.

Cap content at 768-960px via PageShell width tiers, add muted outer margins, and limit gua grid to four columns.

Co-authored-by: Cursor <cursoragent@cursor.com>

components/layout/mode-workspace.tsx

@@ -1,7 +1,6 @@
 "use client";
 
 import { Sparkles } from "lucide-react";
-import { MODE_CONTAINER } from "@/lib/layout";
 
 export function ModeWorkspace({
   children,
@@ -13,7 +12,7 @@ export function ModeWorkspace({
   aiTitle?: string;
 }) {
   return (
-    <div className={`${MODE_CONTAINER} py-6 lg:py-8`}>
+    <div className="py-6 lg:py-8">
       <div className="grid gap-6 lg:grid-cols-2 lg:items-stretch lg:gap-8 xl:gap-10">
         <div className="grid h-full min-h-0 auto-rows-fr gap-5 lg:min-h-[calc(100vh-9rem)]">
           {children}