Add media-apps stack to ArgoCD

Why:
The media stack (jellyfin plus the sonarr/radarr/prowlarr/bazarr/nzbget/
jellyseerr apps) runs in the media-apps namespace but is deployed out-of-band
by terraform-k8s rather than GitOps. Bringing it under ArgoCD makes the stack
declarative, self-healing, and consistent with every other cluster workload,
and prepares terraform-k8s to drop the media-apps config.

How:
- Add a media AppProject scoped to the media-apps namespace and a media-apps
  ApplicationSet that renders one Application per app plus a shared foundation.
- Add a shared media-apps foundation (namespace, media-apps-vault-reader
  ServiceAccount, default VaultAuth on k8s/au/syd1, and the RWX movies/tvseries
  library PVCs) that the whole stack mounts.
- Add per-app kustomize base and au-syd1 overlay for jellyfin and the six *arr
  apps, using plain resource names (jellyfin, sonarr, ...) with fresh PVCs.
- Deploy jellyfin from the jellyfin-ha fork (Redis transcode store, RWX
  transcode scratch) wired to the shared movies/tvseries library PVCs, keeping
  the intel iGPU nodeSelector and gpu.intel.com/i915 request.
- Source API keys and nzbget credentials through VSO VaultStaticSecrets from
  kv/service/media-apps/<app>; expose each app via a traefik-internal Gateway
  and HTTPRoute at <app>.k8s.syd1.au.unkin.net.
- Register the media project and applicationset in the argocd bootstrap
  kustomizations.

apps/base/radarr/gateway.yaml

@@ -0,0 +1,37 @@
+---
+apiVersion: gateway.networking.k8s.io/v1
+kind: Gateway
+metadata:
+  labels:
+    traefik.io/instance: internal
+  annotations:
+    cert-manager.io/cluster-issuer: vault-issuer
+    cert-manager.io/common-name: radarr.k8s.syd1.au.unkin.net
+    cert-manager.io/private-key-size: "4096"
+    external-dns.alpha.kubernetes.io/hostname: radarr.k8s.syd1.au.unkin.net
+    external-dns.alpha.kubernetes.io/target: 198.18.200.4
+  name: radarr
+  namespace: media-apps
+spec:
+  gatewayClassName: traefik-internal
+  listeners:
+    - allowedRoutes:
+        namespaces:
+          from: Same
+      hostname: radarr.k8s.syd1.au.unkin.net
+      name: http
+      port: 80
+      protocol: HTTP
+    - allowedRoutes:
+        namespaces:
+          from: Same
+      hostname: radarr.k8s.syd1.au.unkin.net
+      name: https
+      port: 443
+      protocol: HTTPS
+      tls:
+        certificateRefs:
+          - group: ""
+            kind: Secret
+            name: radarr-tls
+        mode: Terminate