B2B-13 · Real health checks (terminus: Mongo + Kratos, readiness/liveness)

[thesocialdev]

Part of the B2B epic (Bloco 3 · item 3.4). Quick win, fully independent. Today server/root.controller.ts:17-20 returns hardcoded {status:"ok"}; @nestjs/terminus is not a dependency.

What

• Add @nestjs/terminus
• Mongo + Kratos health indicators
• Readiness/liveness endpoints (wire to k8s probes in deployment/)

Effort: ~0.5 SP · Depends on: —