feat(case-ui): overview body — wider documents column (X17 18j)

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

web-ui/src/app/cases/[caseNumber]/page.tsx

@@ -149,8 +149,8 @@ export default function CaseDetailPage({
             StatusRail (banner A, X17), so every tab keeps the status context. */}
         <div className="min-w-0 mt-6">
           <TabsContent value="overview" className="mt-0">
-            {/* documents + agents two-column (mockup 18j) */}
-            <div className="grid gap-6 lg:grid-cols-2 items-start">
+            {/* documents (wider) + agent-activity preview (mockup 18j) */}
+            <div className="grid gap-6 lg:grid-cols-[1.4fr_1fr] items-start">
               <DocumentsPanel data={data} />
               <AgentActivityPreview caseNumber={caseNumber} />
             </div>