refactor(app): move site routes into a (frontend) route group

Payload's admin panel ships its own root layout rendering html/body.
Next allows multiple root layouts only when no app/layout.tsx exists, so
the site's routes move into their own group. Route groups are invisible
to routing: every public URL is unchanged, verified against the build's
route table.

The metadata file conventions deliberately stay at the app/ root. Moving
them into the group renamed /icon.png to /icon-4usi79.png (likewise
apple-icon and opengraph-image) and dropped /robots.txt altogether,
which would have broken the /icon.png cache-control rule, the
outputFileTracingIncludes entry for the share card, and robots.txt.

darkThemeSafety reads app/globals.css off disk rather than importing it,
so it needed its own path fix — a grep for import specifiers misses it,
and it fails as an unrunnable suite rather than a failed assertion.

Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_017YmbBhr8s7GusjDE12hrZM

nextjs-app/app/(frontend)/rankings/page.tsx

@@ -0,0 +1,86 @@
+/**
+ * Rankings Page (SSR)
+ * Display top-ranked schools by various metrics
+ */
+
+import { fetchRankings, fetchFilters, fetchMetrics } from '@/lib/api';
+import { RankingsView } from '@/components/RankingsView';
+import { absoluteUrl } from '@/lib/site';
+import type { Metadata } from 'next';
+
+interface RankingsPageProps {
+  searchParams: Promise<{
+    metric?: string;
+    local_authority?: string;
+    year?: string;
+    phase?: string;
+  }>;
+}
+
+export const metadata: Metadata = {
+  // 'School Rankings' matched nothing anyone types. League tables is the
+  // phrase parents actually search, and it spikes each results day.
+  title: { absolute: 'Primary & Secondary School League Tables | schoolcompare' },
+  description:
+    'Rank English schools by SATs results, GCSEs, Progress 8 or Attainment 8, and filter by local authority or year. Built from the DfE’s own figures.',
+  keywords: 'school rankings, top schools, best schools, KS2 rankings, KS4 rankings, school league tables',
+  // Param forms (?metric=&local_authority=&year=&phase=) collapse here for
+  // now. W3 replaces them with real indexable paths.
+  alternates: { canonical: absoluteUrl('/rankings') },
+};
+
+// Dynamic via searchParams; remove force-dynamic so internal data fetches
+// can still use Next.js's per-call revalidate cache.
+
+export default async function RankingsPage({ searchParams }: RankingsPageProps) {
+  const { metric: metricParam, local_authority, year: yearParam, phase: phaseParam } = await searchParams;
+
+  const phase = phaseParam || 'primary';
+  const metric = metricParam || (phase === 'secondary' ? 'attainment_8_score' : 'rwm_expected_pct');
+  const year = yearParam ? parseInt(yearParam) : undefined;
+
+  // Fetch rankings data with error handling
+  try {
+    const [rankingsResponse, filtersResponse, metricsResponse] = await Promise.all([
+      fetchRankings({
+        metric,
+        local_authority,
+        year,
+        limit: 100,
+        phase,
+      }),
+      fetchFilters(),
+      fetchMetrics(),
+    ]);
+
+    // Metrics is already an array
+    const metricsArray = metricsResponse?.metrics || [];
+
+    return (
+      <RankingsView
+        rankings={rankingsResponse?.rankings || []}
+        filters={filtersResponse || { local_authorities: [], school_types: [], years: [], phases: [], genders: [], admissions_policies: [] }}
+        metrics={metricsArray}
+        selectedMetric={metric}
+        selectedArea={local_authority}
+        selectedYear={year}
+        selectedPhase={phase}
+      />
+    );
+  } catch (error) {
+    console.error('Error fetching data for rankings page:', error);
+
+    // Return error state with empty data
+    return (
+      <RankingsView
+        rankings={[]}
+        filters={{ local_authorities: [], school_types: [], years: [], phases: [], genders: [], admissions_policies: [] }}
+        metrics={[]}
+        selectedMetric={metric}
+        selectedArea={local_authority}
+        selectedYear={year}
+        selectedPhase={phase}
+      />
+    );
+  }
+}