chore: planning docs + backend/frontend scaffold + MVP Prisma schema

- CLAUDE.md, ARCHITECTURE.md, TASKS.md per Lastenheft-Vorgabe
- ApiCore-Backend: NestJS scaffold, Prisma 7 (DATABASE_URL via prisma.config.ts)
- ApiCore-Frontend: Next.js App Router scaffold (TS, Tailwind, ESLint)
- prisma/schema.prisma: alle MVP-Entitaeten aus Abschnitt 13/4.2-4.22/26,
  validiert und Client generiert

Grundgeruest (TASKS.md #0) noch nicht vollstaendig: shadcn/ui, TanStack Query,
PWA-Manifest, deploy/k8s/, Dockerfiles fehlen noch.

ApiCore-Backend/test/jest-e2e.json

@@ -0,0 +1,9 @@
+{
+  "moduleFileExtensions": ["js", "json", "ts"],
+  "rootDir": ".",
+  "testEnvironment": "node",
+  "testRegex": ".e2e-spec.ts$",
+  "transform": {
+    "^.+\\.(t|j)s$": "ts-jest"
+  }
+}