feat: Grundgeruest fertigstellen (Backend/Frontend/K8s)

Backend: Prisma-Client auf prisma-client-js + Driver-Adapter (@prisma/adapter-pg)
umgestellt (Prisma 7 verlangt Adapter, ESM-Client brach an Jest), erste Migration
erzeugt und angewendet, /api/v1 Versioning, Swagger unter /api/v1/docs, Helmet,
globale ValidationPipe, PrismaModule, HealthModule (/health, /health/ready mit
DB-Check), tsconfig.build.json Root-Dir-Fix (dist/main.js statt dist/src/main.js).

Frontend: Tailwind v4 + shadcn/ui initialisiert, TanStack Query Provider, PWA
Manifest (app/manifest.ts), Vitest + Testing Library Setup, next.config output
standalone.

deploy/k8s: Dockerfiles (Backend/Frontend, Multi-Stage) + Deployment/Service/
Ingress/ConfigMap/Secret-Vorlagen fuer beide Projekte.

Lokale Dev-/Test-Postgres-Instanz unter ApiCore-Backend/.devdb angelegt (eigene
Rolle, kein bestehendes Passwort noetig), .env/.env.test lokal befuellt.

Lint, Typecheck, Tests und Build sind fuer Backend und Frontend gruen; Server
wurde lokal gestartet und /health, /health/ready, /api/v1/docs manuell verifiziert.

ApiCore-Backend/src/health/health.controller.ts

@@ -0,0 +1,29 @@
+import {
+  Controller,
+  Get,
+  ServiceUnavailableException,
+  VERSION_NEUTRAL,
+} from '@nestjs/common';
+import { ApiTags } from '@nestjs/swagger';
+import { PrismaService } from '../prisma/prisma.service';
+
+@ApiTags('health')
+@Controller({ path: 'health', version: VERSION_NEUTRAL })
+export class HealthController {
+  constructor(private readonly prisma: PrismaService) {}
+
+  @Get()
+  liveness(): { status: 'ok' } {
+    return { status: 'ok' };
+  }
+
+  @Get('ready')
+  async readiness(): Promise<{ status: 'ok' }> {
+    try {
+      await this.prisma.$queryRaw`SELECT 1`;
+      return { status: 'ok' };
+    } catch {
+      throw new ServiceUnavailableException('Database not reachable');
+    }
+  }
+}