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

mattermost/versions/12/deployment.yaml

@@ -0,0 +1,93 @@
+apiVersion: apps/v1
+kind: Deployment
+metadata:
+  name: mattermost
+  namespace: mattermost
+spec:
+  replicas: 1
+  strategy:
+    type: Recreate
+  selector:
+    matchLabels:
+      component: web
+  template:
+    metadata:
+      labels:
+        component: web
+    spec:
+      securityContext:
+        runAsNonRoot: true
+        runAsUser: 2000
+        runAsGroup: 2000
+        fsGroup: 2000
+        seccompProfile:
+          type: RuntimeDefault
+      containers:
+        - name: mattermost
+          image: mattermost/mattermost-team-edition:12.0.1
+          ports:
+            - name: http
+              containerPort: 8065
+              protocol: TCP
+          env:
+            - name: MM_SERVICESETTINGS_SITEURL
+              value: https://{{ .domain }}
+            - name: MM_SQLSETTINGS_DRIVERNAME
+              value: postgres
+            - name: MM_SQLSETTINGS_DATASOURCE
+              valueFrom:
+                secretKeyRef:
+                  name: mattermost-secrets
+                  key: dbUrl
+            - name: MM_FILESETTINGS_DIRECTORY
+              value: /mattermost/data/
+            - name: MM_PLUGINSETTINGS_PLUGINDIRECTORY
+              value: /mattermost/plugins
+            - name: MM_CLIENTPLUGINSSETTINGS_PLUGINDIRECTORY
+              value: /mattermost/client/plugins
+            - name: MM_LOGSETTINGS_CONSOLELEVEL
+              value: INFO
+          resources:
+            limits:
+              cpu: 500m
+              ephemeral-storage: 1Gi
+              memory: 1Gi
+            requests:
+              cpu: 50m
+              ephemeral-storage: 50Mi
+              memory: 256Mi
+          volumeMounts:
+            - name: mattermost-data
+              mountPath: /mattermost/data
+            - name: mattermost-plugins
+              mountPath: /mattermost/plugins
+          livenessProbe:
+            httpGet:
+              path: /api/v4/system/ping
+              port: 8065
+            initialDelaySeconds: 60
+            timeoutSeconds: 5
+            periodSeconds: 15
+            failureThreshold: 6
+          readinessProbe:
+            httpGet:
+              path: /api/v4/system/ping
+              port: 8065
+            initialDelaySeconds: 30
+            timeoutSeconds: 3
+            periodSeconds: 10
+            failureThreshold: 3
+          securityContext:
+            allowPrivilegeEscalation: false
+            capabilities:
+              drop:
+                - ALL
+            readOnlyRootFilesystem: false
+      volumes:
+        - name: mattermost-data
+          persistentVolumeClaim:
+            claimName: mattermost-data
+        - name: mattermost-plugins
+          persistentVolumeClaim:
+            claimName: mattermost-plugins
+      restartPolicy: Always