feat: Prisma schema, migrations en seed voor auth en audit-log

- Models: User, Session, FlowRun, FlowStep met FlowStatus enum
- prisma.config.ts met DATABASE_URL via @prisma/adapter-pg (Prisma 7 API)
- Initiële migratie applied op ops_dashboard database
- Seed-script voor 1 user via SEED_USER_EMAIL/SEED_USER_PASSWORD env-vars
- lib/prisma.ts als gedeelde singleton client voor Next.js

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

package.json

@@ -5,14 +5,25 @@
   "scripts": {
     "dev": "next dev",
     "build": "next build",
-    "start": "next start"
+    "start": "next start",
+    "db:seed": "ts-node --esm prisma/seed.ts"
+  },
+  "prisma": {
+    "seed": "ts-node --esm prisma/seed.ts"
   },
   "dependencies": {
     "@base-ui/react": "^1.4.1",
+    "@prisma/adapter-pg": "^7.8.0",
+    "@prisma/client": "^7.8.0",
+    "@types/bcryptjs": "^2.4.6",
+    "@types/pg": "^8.20.0",
+    "bcryptjs": "^3.0.3",
     "class-variance-authority": "^0.7.1",
     "clsx": "^2.1.1",
     "lucide-react": "^1.14.0",
     "next": "16.2.6",
+    "pg": "^8.20.0",
+    "prisma": "^7.8.0",
     "react": "19.2.4",
     "react-dom": "19.2.4",
     "shadcn": "^4.7.0",
@@ -25,6 +36,7 @@
     "@types/react": "^19",
     "@types/react-dom": "^19",
     "tailwindcss": "^4",
+    "ts-node": "^10.9.2",
     "typescript": "^5"
   }
 }