fix(cert-manager): restore wildcard renewal and drop per-host TLS

The ACME DNS-01 self-check resolved through CoreDNS and never saw the TXT
record. The wildcard renewal stalled on 2026-09-23 and riotpiao-com-tls
expired on 2026-10-23. Every Cloudflare Tunnel origin then failed with
"x509: certificate has expired or is not yet valid".

Changes:

- cert-manager: pin the self-check to the public resolvers with
  --dns01-recursive-nameservers and --dns01-recursive-nameservers-only.
  Verified against Let's Encrypt staging: the challenge went valid and the
  certificate issued.
- comfyui and forgejo: drop the per-host tls blocks and the
  cert-manager.io/cluster-issuer annotations. The wildcard covers both
  hosts, and the per-host certificates (comfyui-tls, forgejo-tls) expired
  with the wildcard.
- riotpiao-com-cert: document the wildcard as nginx's default certificate
  and the zero-downtime renewal path.

Renewal now runs 30 days before expiry, writes the same secret, and nginx
hot-reloads without a pod restart.

k8s/apps/comfyui/ingress.yaml

@@ -4,7 +4,9 @@ metadata:
   name: comfyui
   namespace: comfyui
   annotations:
-    cert-manager.io/cluster-issuer: letsencrypt-prod
+    # No cert-manager annotation and no tls: block. This host is covered by
+    # the *.riotpiao.com wildcard, which nginx serves as its
+    # default-ssl-certificate (ingress-nginx/riotpiao-com-tls).
     nginx.ingress.kubernetes.io/proxy-read-timeout: "600"
     nginx.ingress.kubernetes.io/proxy-send-timeout: "600"
     nginx.ingress.kubernetes.io/proxy-body-size: "0"
@@ -16,10 +18,6 @@ metadata:
       proxy_set_header Connection "upgrade";
 spec:
   ingressClassName: nginx
-  tls:
-    - secretName: comfyui-tls
-      hosts:
-        - comfyui.riotpiao.com
   rules:
     - host: comfyui.riotpiao.com
       http:

k8s/bootstrap/cert-manager/cert-manager-values.yaml

@@ -8,6 +8,19 @@
 # depend on them existing first.
 installCRDs: true
 
+# Point the ACME DNS-01 self-check at the public resolvers directly.
+#
+# Without these flags cert-manager resolves through the pod resolver
+# (CoreDNS at 10.96.0.10). The self-check then never saw the TXT record and
+# reported "Waiting for DNS-01 challenge propagation" forever. The wildcard
+# certificate renewal stalled on 2026-09-23 and the cert expired on
+# 2026-10-23, which broke every Cloudflare Tunnel origin with
+# "x509: certificate has expired".
+#
+extraArgs:
+  - --dns01-recursive-nameservers=1.1.1.1:53,8.8.8.8:53
+  - --dns01-recursive-nameservers-only
+
 # Tolerate the control-plane taint (talos-cp-1 is the only schedulable node).
 tolerations:
   - key: node-role.kubernetes.io/control-plane

k8s/bootstrap/ingress/riotpiao-com-cert.yaml

@@ -1,13 +1,21 @@
 # k8s/bootstrap/ingress/riotpiao-com-cert.yaml
 # Public wildcard cert for *.riotpiao.com, signed by Let's Encrypt (DNS-01 via
-# Cloudflare, see ../cert-manager/letsencrypt-issuer.yaml). Distinct from
-# homelab-tls (self-signed homelab-ca, internal *.riotpiao.com) —
-# reference riotpiao-com-tls explicitly on ingresses that expose riotpiao.com
-# hosts to the internet; it is not nginx's default-ssl-certificate.
+# Cloudflare, see ../cert-manager/letsencrypt-issuer.yaml).
 #
-# issuerRef starts on letsencrypt-staging. Switch to letsencrypt-prod once the
-# staging cert issues cleanly, then delete this Certificate's Secret to force
-# a re-issue against prod (staging certs aren't browser-trusted).
+# nginx serves this secret as its default-ssl-certificate
+# (../ingress/nginx-values.yaml), so every Ingress that omits a tls: block uses
+# it. Do not add per-host tls: blocks for *.riotpiao.com hosts: they create a
+# second, single-host certificate and split the wildcard coverage.
+#
+# Renewal is automatic and does not drop traffic:
+#   - cert-manager starts a new order 30 days before expiry (renewBefore).
+#   - cert-manager writes the renewed pair into the same secret.
+#   - ingress-nginx watches the secret and hot-reloads. No pod restart.
+#   - The old pair stays valid until the new one is written, so no gap exists.
+#
+# The DNS-01 self-check must reach the public resolvers directly. Without the
+# --dns01-recursive-nameservers flags in ../../cert-manager/cert-manager-values.yaml
+# the self-check never sees the TXT record and renewal stalls until expiry.
 apiVersion: cert-manager.io/v1
 kind: Certificate
 metadata:

k8s/bootstrap/phase3-forgejo/forgejo-values.yaml

@@ -107,7 +107,9 @@ ingress:
   enabled: true
   className: nginx
   annotations:
-    cert-manager.io/cluster-issuer: letsencrypt-prod
+    # No cert-manager annotation. forgejo.riotpiao.com is covered by the
+    # *.riotpiao.com wildcard, served as nginx's default-ssl-certificate.
+    #
     # This chart Ingress and the hand-written one in
     # k8s/bootstrap/ingress/ingress.yaml both claim forgejo.riotpiao.com.
     # ingress-nginx breaks the tie by oldest creationTimestamp, and the chart's
@@ -125,10 +127,9 @@ ingress:
       paths:
         - path: /
           pathType: Prefix
-  tls:
-    - secretName: forgejo-tls
-      hosts:
-        - forgejo.riotpiao.com
+  # tls: intentionally omitted. The chart would create a second, single-host
+  # certificate (forgejo-tls) that expired on 2026-10-23 and competed with the
+  # wildcard. The wildcard covers this host.
 
 # Resources
 resources: