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>

src/lib/prisma.ts

@@ -0,0 +1,15 @@
+import { PrismaClient } from '@prisma/client'
+
+const globalForPrisma = globalThis as unknown as {
+  prisma: PrismaClient | undefined
+}
+
+export const prisma =
+  globalForPrisma.prisma ??
+  new PrismaClient({
+    log: process.env.NODE_ENV === 'development' ? ['query', 'error', 'warn'] : ['error'],
+  })
+
+if (process.env.NODE_ENV !== 'production') {
+  globalForPrisma.prisma = prisma
+}

src/lib/utils.ts

@@ -0,0 +1,58 @@
+import { type ClassValue, clsx } from 'clsx'
+import { twMerge } from 'tailwind-merge'
+
+/**
+ * Merge Tailwind CSS classes with proper precedence
+ */
+export function cn(...inputs: ClassValue[]) {
+  return twMerge(clsx(inputs))
+}
+
+/**
+ * Format number with Portuguese locale
+ * @example formatNumber(1234567) => "1.234.567"
+ */
+export function formatNumber(num: number): string {
+  return new Intl.NumberFormat('pt-PT').format(num)
+}
+
+/**
+ * Format number as percentage
+ * @example formatPercent(0.1234) => "12,3%"
+ */
+export function formatPercent(num: number, decimals: number = 1): string {
+  return `${(num * 100).toFixed(decimals)}%`
+}
+
+/**
+ * Format number as compact (K, M, B)
+ * @example formatCompact(1234567) => "1,2M"
+ */
+export function formatCompact(num: number): string {
+  return new Intl.NumberFormat('pt-PT', {
+    notation: 'compact',
+    compactDisplay: 'short',
+  }).format(num)
+}
+
+/**
+ * Format date as Portuguese short date
+ * @example formatDate(new Date()) => "13/02/2026"
+ */
+export function formatDate(date: Date | string): string {
+  const d = typeof date === 'string' ? new Date(date) : date
+  return new Intl.DateTimeFormat('pt-PT', {
+    day: '2-digit',
+    month: '2-digit',
+    year: 'numeric',
+  }).format(d)
+}
+
+/**
+ * Calculate percentage change
+ * @example calculateChange(100, 120) => 20
+ */
+export function calculateChange(oldValue: number, newValue: number): number {
+  if (oldValue === 0) return 0
+  return ((newValue - oldValue) / oldValue) * 100
+}