Bump remaining apps: major version slots and infrastructure

New version slots (major version jumps):
- gitea: 1.24.3 -> 28.2.0 (slot 1 -> 28)
- ghost: 5.130.6 -> 6.72.0 (slot 5 -> 6)
- formbricks: 3.6.0 -> 6.1.0 (slot 3 -> 6)
- mattermost: 10.8.1 -> 12.0.1 (slot 10 -> 12)
- zulip: 9.4 -> 12.3 (slot 9 -> 12)
- immich: 1.135.3 -> 3.3.5 (slot 1 -> 3)
- openproject: 16.1.1 -> 17.9.3 (slot 16 -> 17)
- listmonk: 5.0.3 -> 6.1.0 (slot 5 -> 6)
- discourse: 3.5.3 -> 2026.10.0 (slot 3 -> 2026, calver)

Same-slot large bumps:
- vllm: 0.9.2 -> 0.32.0
- longhorn: v1.8.1 -> v1.13.0

Infrastructure:
- cert-manager: v1.17.2 -> v1.21.2
- coredns: v1.12.0 -> v1.14.7
- externaldns: v0.13.4 -> v0.23.0
- metallb: v0.15.0 -> v0.16.1
- mysql: 9.1.0 -> 9.7.4
- node-feature-discovery: v0.17.3 -> v0.20.1
- nvidia-device-plugin: v0.17.1 -> v0.20.1

externaldns/versions/v0/externaldns-cloudflare.yaml

@@ -22,7 +22,7 @@ spec:
           type: RuntimeDefault
       containers:
         - name: external-dns
-          image: registry.k8s.io/external-dns/external-dns:v0.13.4
+          image: registry.k8s.io/external-dns/external-dns:v0.23.0
           args:
             - --source=service
             - --source=ingress