fix(ui): make project detail and scenario pages full width

Replace max-w-5xl/max-w-7xl constrained wrappers with the app-page utility
class, consistent with other full-width pages like the projects list.

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

apps/web/src/app/(app)/projects/[id]/page.tsx

@@ -37,7 +37,7 @@ export default async function ProjectDetailPage({ params }: ProjectDetailPagePro
   const unfilledSeats = activeDemands.reduce((sum, demand) => sum + demand.unfilledHeadcount, 0);
 
   return (
-    <div className="p-6 max-w-5xl mx-auto space-y-6">
+    <div className="app-page space-y-6">
       {/* Back link */}
       <Link
         href="/projects"

apps/web/src/app/(app)/projects/[id]/scenario/page.tsx

@@ -25,7 +25,7 @@ export default async function ScenarioPage({ params }: ScenarioPageProps) {
   ]);
 
   return (
-    <div className="p-6 max-w-7xl mx-auto space-y-6">
+    <div className="app-page space-y-6">
       <Link
         href={`/projects/${id}`}
         className="inline-flex items-center gap-1 text-sm text-gray-500 hover:text-gray-800 transition-colors"