Add jellyfin (HA fork) app under a new media project

Deploys the jellyfin-ha fork (git.unkin.net/unkin/jellyfin-ha) to au-syd1
via ArgoCD, under a dedicated media AppProject/ApplicationSet rather than
extending platform.

- New media AppProject + media-apps ApplicationSet (watches
  apps/overlays/*/jellyfin); registered in the argocd kustomizations
- apps/base/jellyfin: namespace, deployment (single replica to start),
  service, in-namespace Redis (transcode session store), gateway + httproute
  at jellyfin.k8s.syd1.au.unkin.net
- Storage: RWO config (cephrbd), RWX transcode scratch and RWX media
  library (cephfs) per the HA fork's pod-takeover requirement
- au-syd1 overlay

apps/base/jellyfin/redis-deployment.yaml

@@ -0,0 +1,66 @@
+---
+apiVersion: apps/v1
+kind: Deployment
+metadata:
+  name: redis
+  namespace: jellyfin
+spec:
+  replicas: 1
+  selector:
+    matchLabels:
+      app: redis
+  strategy:
+    type: Recreate
+  template:
+    metadata:
+      labels:
+        app: redis
+    spec:
+      containers:
+        - name: redis
+          image: redis:7-alpine
+          imagePullPolicy: IfNotPresent
+          command:
+            - redis-server
+            - --save
+            - "20"
+            - "1"
+          ports:
+            - containerPort: 6379
+              name: redis
+              protocol: TCP
+          livenessProbe:
+            exec:
+              command:
+                - redis-cli
+                - ping
+            failureThreshold: 3
+            initialDelaySeconds: 30
+            periodSeconds: 30
+            successThreshold: 1
+            timeoutSeconds: 5
+          readinessProbe:
+            exec:
+              command:
+                - redis-cli
+                - ping
+            failureThreshold: 3
+            initialDelaySeconds: 5
+            periodSeconds: 10
+            successThreshold: 1
+            timeoutSeconds: 5
+          resources:
+            limits:
+              cpu: 500m
+              memory: 512Mi
+            requests:
+              cpu: 50m
+              memory: 128Mi
+          volumeMounts:
+            - mountPath: /data
+              name: data
+      restartPolicy: Always
+      volumes:
+        - name: data
+          persistentVolumeClaim:
+            claimName: jellyfin-redis-data