chore(ops): split /api/health (liveness) from /api/ready (readiness)

Previously /api/health did deep dependency probes (postgres + redis +
minio) and 503'd on any failure. That's readiness behavior, not
liveness — a transient Redis/MinIO blip would tell the orchestrator to
restart the pod when it should only be dropped from the load balancer.

Make /api/health a thin liveness check (returns 200 unconditionally if
the process is responding) and move the deep checks to a new
/api/ready endpoint with the canonical Kubernetes-style 200/503
contract. Docker-compose healthchecks keep pointing at /api/health,
which is now more conservative (no false-positive container restarts).

Documenso/SMTP are intentionally not probed in /api/ready: each tenant
configures its own credentials and a tenant misconfiguration shouldn't
deadline the entire shared CRM.

Also tighten the gdpr-bundle-builder casts: replace the scattered
`as unknown as Record<string, unknown>` double-casts with a small
`toJsonRow<T>()` helper that does the widen narrow→wide in one place
with one cast hop instead of two.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

tests/integration/health-and-ready.test.ts

@@ -0,0 +1,33 @@
+import { describe, it, expect } from 'vitest';
+
+import { GET as healthGet } from '@/app/api/health/route';
+import { GET as readyGet } from '@/app/api/ready/route';
+
+describe('GET /api/health (liveness)', () => {
+  it('returns 200 + status=ok regardless of downstream dependency state', async () => {
+    const res = await healthGet();
+    expect(res.status).toBe(200);
+    const body = await res.json();
+    expect(body.status).toBe('ok');
+    expect(body.timestamp).toMatch(/^\d{4}-\d{2}-\d{2}T/);
+  });
+});
+
+describe('GET /api/ready (readiness)', () => {
+  it('returns ready=200 when postgres + redis + minio all answer', async () => {
+    // The dev/test environment has all three reachable; this covers the
+    // happy path. The degraded path is not exercised here because
+    // simulating a down dep without leaking into other tests is awkward;
+    // the route's logic is intentionally trivial (Promise.allSettled +
+    // every-ok check) and worth covering at the unit level only.
+    const res = await readyGet();
+    expect(res.status).toBe(200);
+    const body = await res.json();
+    expect(body.status).toBe('ready');
+    expect(body.checks).toEqual({
+      postgres: 'ok',
+      redis: 'ok',
+      minio: 'ok',
+    });
+  });
+});