fix(certs): kill cert-manager renewal loop on 3 broken Certificate specs

Three Certificates requested duration: 2160h (90d) with renewBefore: 720h
(30d). step-ca's ACME provisioner caps cert lifetime at 30d, so it silently
issued 720h certs — making renewBefore EQUAL to the actual cert lifetime.
cert-manager treats the cert as needing immediate renewal the moment it's
issued, creates a CertificateRequest, gets a new (still 30d) cert, marks
it for immediate renewal, and loops.

Damage on 2026-05-07 ~20:30 (caught during regroup after 5h gap):
  - fc-worldbuilder/worldbuilder-web-tls:  2365 CRs in 18h
  - fc-distribution/fc-distribution-tls:  10880 CRs in 18h
  - knowledge/knowledge-tls:              10888 CRs in 18h
  Total: 24,133 stale CertificateRequest objects in etcd.

Bulk-deleted all CRs + Orders in those 3 namespaces, then this commit
fixes the source so ArgoCD sync stops re-creating the loop.

Fix: match the working 720h/240h pattern used by every other FC service
cert (agent-zero, fc-dns, fc-llm-bridge, fc-php, traefik-system, etc.).
30d cert lifetime + 10d renewal headroom = renewal at day 20, which is
the cert-manager standard 2/3-of-lifetime practice.

Side effect during loop: ALSO contributed to step-ca load and may have
caused intermittent timeouts cluster-wide (the latest stuck challenge
was timing out dialing step-ca:9443 even though step-ca itself was up).

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

apps/knowledge/knowledge.yaml

@@ -241,8 +241,12 @@ spec:
     kind: ClusterIssuer
   dnsNames:
     - knowledge.iamworkin.lan
-  duration: 2160h    # 90d
-  renewBefore: 720h  # 30d
+  # step-ca ACME caps lifetime at 30d; requesting 90d silently capped
+  # made renewBefore=cert-lifetime → perpetual renewal loop (10888+ CRs
+  # in 18h on 2026-05-07). Match working 720h/240h pattern from other
+  # FC services.
+  duration: 720h     # 30d (step-ca cap)
+  renewBefore: 240h  # 10d
 ---
 apiVersion: traefik.io/v1alpha1
 kind: IngressRoute