Add Web Vitals performance tracking (LCP, INP, CLS, FCP, TTFB)

End-to-end performance metrics tracking: dedicated database table with
percentile aggregation, tracker collection behind data-perf attribute,
/api/send handling, report API endpoints, and Performance dashboard page
with threshold-based metric cards, time-series chart, and per-page breakdown.

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

src/app/api/reports/performance/route.ts

@@ -0,0 +1,26 @@
+import { getQueryFilters, parseRequest, setWebsiteDate } from '@/lib/request';
+import { json, unauthorized } from '@/lib/response';
+import { reportResultSchema } from '@/lib/schema';
+import { canViewWebsite } from '@/permissions';
+import { getPerformance, type PerformanceParameters } from '@/queries/sql/reports/getPerformance';
+
+export async function POST(request: Request) {
+  const { auth, body, error } = await parseRequest(request, reportResultSchema);
+
+  if (error) {
+    return error();
+  }
+
+  const { websiteId } = body;
+
+  if (!(await canViewWebsite(auth, websiteId))) {
+    return unauthorized();
+  }
+
+  const parameters = await setWebsiteDate(websiteId, body.parameters);
+  const filters = await getQueryFilters(body.filters, websiteId);
+
+  const data = await getPerformance(websiteId, parameters as PerformanceParameters, filters);
+
+  return json(data);
+}