feat: PostgreSQL support en Vercel CI/CD deployment

- Prisma schema: sqlite → postgresql provider met directUrl
- prisma.config.ts: directUrl toegevoegd
- seed.ts: dynamisch SQLite of PostgreSQL adapter op basis van DATABASE_URL
- ci.yml: preview deploy op PR, productie deploy op push naar main

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

.github/workflows/ci.yml

@@ -32,8 +32,6 @@ jobs:
 
       - name: Prisma validate
         run: npx prisma validate
-        env:
-          DATABASE_URL: file:./dev.db
 
       - name: Test
         run: npm test
@@ -41,6 +39,68 @@ jobs:
       - name: Build
         run: npm run build
         env:
-          DATABASE_URL: file:./dev.db
-          DIRECT_URL: file:./dev.db
-          SESSION_SECRET: ${{ secrets.SESSION_SECRET || 'ci-placeholder-secret-must-be-32-chars-min' }}
+          DATABASE_URL: ${{ secrets.DATABASE_URL }}
+          DIRECT_URL: ${{ secrets.DIRECT_URL }}
+          SESSION_SECRET: ${{ secrets.SESSION_SECRET }}
+
+  deploy-preview:
+    name: Deploy Preview (PR)
+    runs-on: ubuntu-latest
+    needs: ci
+    if: github.event_name == 'pull_request'
+
+    steps:
+      - name: Checkout
+        uses: actions/checkout@v4
+
+      - name: Setup Node.js
+        uses: actions/setup-node@v4
+        with:
+          node-version: '20'
+          cache: 'npm'
+
+      - name: Install dependencies
+        run: npm ci
+
+      - name: Install Vercel CLI
+        run: npm install -g vercel@latest
+
+      - name: Deploy Preview to Vercel
+        run: vercel deploy --token=${{ secrets.VERCEL_TOKEN }}
+        env:
+          VERCEL_ORG_ID: ${{ secrets.VERCEL_ORG_ID }}
+          VERCEL_PROJECT_ID: ${{ secrets.VERCEL_PROJECT_ID }}
+
+  deploy-production:
+    name: Deploy Production (main)
+    runs-on: ubuntu-latest
+    needs: ci
+    if: github.ref == 'refs/heads/main' && github.event_name == 'push'
+
+    steps:
+      - name: Checkout
+        uses: actions/checkout@v4
+
+      - name: Setup Node.js
+        uses: actions/setup-node@v4
+        with:
+          node-version: '20'
+          cache: 'npm'
+
+      - name: Install dependencies
+        run: npm ci
+
+      - name: Install Vercel CLI
+        run: npm install -g vercel@latest
+
+      - name: Run database migrations
+        run: npx prisma migrate deploy
+        env:
+          DATABASE_URL: ${{ secrets.DATABASE_URL }}
+          DIRECT_URL: ${{ secrets.DIRECT_URL }}
+
+      - name: Deploy Production to Vercel
+        run: vercel deploy --prod --token=${{ secrets.VERCEL_TOKEN }}
+        env:
+          VERCEL_ORG_ID: ${{ secrets.VERCEL_ORG_ID }}
+          VERCEL_PROJECT_ID: ${{ secrets.VERCEL_PROJECT_ID }}