feat(web): add saved searches, image lightbox, and web vitals tracking

New features:
- Saved searches dashboard page with CRUD hooks and API client
- Image lightbox component for property gallery full-screen viewing
- Web vitals provider and reporting utilities for performance monitoring
- Image blur placeholder generation utility

Co-Authored-By: Paperclip <noreply@paperclip.ing>

apps/web/components/providers/web-vitals.tsx

@@ -0,0 +1,42 @@
+'use client';
+
+import { useEffect } from 'react';
+
+/**
+ * Client component that initialises Core Web Vitals reporting.
+ *
+ * Tracks: LCP, FCP, CLS, TTFB, INP (the five web-vitals v5 metrics).
+ * FID was deprecated — INP is the modern responsiveness metric;
+ * FCP (First Contentful Paint) replaces FID in the library.
+ *
+ * Metrics are batched and sent to the backend `/web-vitals` endpoint via
+ * `navigator.sendBeacon` for reliability during page transitions.
+ */
+export function WebVitals() {
+  useEffect(() => {
+    // Dynamic import so the library is only loaded in the browser
+    import('web-vitals').then(({ onLCP, onFCP, onCLS, onTTFB, onINP }) => {
+      import('@/lib/web-vitals').then(({ reportWebVital, flushWebVitals }) => {
+        onLCP(reportWebVital);
+        onFCP(reportWebVital);
+        onCLS(reportWebVital);
+        onTTFB(reportWebVital);
+        onINP(reportWebVital);
+
+        // Flush remaining metrics when the page is hidden (tab switch, close, navigate)
+        const handleVisibilityChange = () => {
+          if (document.visibilityState === 'hidden') {
+            flushWebVitals();
+          }
+        };
+        document.addEventListener('visibilitychange', handleVisibilityChange);
+
+        return () => {
+          document.removeEventListener('visibilitychange', handleVisibilityChange);
+        };
+      });
+    });
+  }, []);
+
+  return null;
+}