Phase 2: Database e API Layer

- Configurado Prisma 7 com multiSchema para staging database
- Models: Site, GA4DailyTraffic, GA4TrafficSources, GSCSearchPerformance
- Created lib utilities (prisma.ts, utils.ts) com formatação PT-PT
- API routes implementadas:
  * GET /api/sites - lista sites activos
  * GET /api/metrics/[siteId]?period=30d - métricas agregadas + charts
  * GET /api/health - health check com conexão DB

Métricas incluem:
- KPIs: visitors, sessions, pageViews, newUsers com % change
- Charts: dailyTraffic, trafficSources, topQueries (GSC)
- Comparação período anterior para trends

Co-Authored-By: Claude Sonnet 4.5 <noreply@anthropic.com>

prisma/prisma.config.ts

@@ -0,0 +1,9 @@
+import { defineConfig } from '@prisma/client/generator-helper'
+
+export default defineConfig({
+  datasources: {
+    db: {
+      url: process.env.DATABASE_URL!,
+    },
+  },
+})