feat: Implement full Phase 3 API optimizations

src/hooks/photos/usePhotoCount.ts

@@ -0,0 +1,28 @@
+import { useQuery } from '@tanstack/react-query';
+import { supabase } from '@/integrations/supabase/client';
+import { queryKeys } from '@/lib/queryKeys';
+
+/**
+ * Hook to fetch photo count for an entity
+ */
+export function usePhotoCount(entityType: string, entityId: string | undefined, enabled = true) {
+  return useQuery({
+    queryKey: ['photos', 'count', entityType, entityId || ''] as const,
+    queryFn: async () => {
+      if (!entityId) return 0;
+
+      const { count, error } = await supabase
+        .from('photos')
+        .select('id', { count: 'exact', head: true })
+        .eq('entity_type', entityType)
+        .eq('entity_id', entityId);
+
+      if (error) throw error;
+      return count || 0;
+    },
+    enabled: enabled && !!entityId,
+    staleTime: 10 * 60 * 1000, // 10 minutes - photo counts change rarely
+    gcTime: 20 * 60 * 1000,
+    refetchOnWindowFocus: false,
+  });
+}