feat(api): add health check endpoints with @nestjs/terminus

Add HealthModule with /health (liveness) and /ready (readiness) probes.
Readiness checks DB (Prisma) and Redis connectivity.
Replaces the basic /health endpoint in AppController.

Co-Authored-By: Paperclip <noreply@paperclip.ing>

apps/api/src/modules/health/infrastructure/prisma.health.ts

@@ -0,0 +1,20 @@
+import { Injectable } from '@nestjs/common';
+import { HealthCheckError, HealthIndicator, type HealthIndicatorResult } from '@nestjs/terminus';
+// eslint-disable-next-line @typescript-eslint/consistent-type-imports
+import { PrismaService } from '@modules/shared/infrastructure/prisma.service';
+
+@Injectable()
+export class PrismaHealthIndicator extends HealthIndicator {
+  constructor(private readonly prisma: PrismaService) {
+    super();
+  }
+
+  async isHealthy(key: string): Promise<HealthIndicatorResult> {
+    try {
+      await this.prisma.$queryRawUnsafe('SELECT 1');
+      return this.getStatus(key, true);
+    } catch {
+      throw new HealthCheckError('Database check failed', this.getStatus(key, false));
+    }
+  }
+}