Add platform-dash: S3 artifact browser for Garage object store

Lightweight Next.js app for browsing, uploading, and downloading
artifacts from the cluster-local Garage S3 bucket. Uses the harness
design system. Features:
- File/folder browser with breadcrumb navigation
- Drag-and-drop upload
- Download and delete
- Ingress at platform.coreworlds.io (internal-only)

Also adds platform-dash to CI/deploy workflows.

infra/kubernetes/platform/traefik/certificate-internal.yaml

@@ -75,3 +75,16 @@ spec:
     kind: ClusterIssuer
   dnsNames:
     - s3.coreworlds.io
+---
+apiVersion: cert-manager.io/v1
+kind: Certificate
+metadata:
+  name: platform-dash-tls
+  namespace: platform
+spec:
+  secretName: platform-dash-tls
+  issuerRef:
+    name: letsencrypt-production
+    kind: ClusterIssuer
+  dnsNames:
+    - platform.coreworlds.io

infra/kubernetes/platform/traefik/ingressroute-platform-dash.yaml

@@ -0,0 +1,22 @@
+apiVersion: traefik.io/v1alpha1
+kind: IngressRoute
+metadata:
+  name: platform-dash
+  namespace: platform
+  annotations:
+    cert-manager.io/cluster-issuer: letsencrypt-production
+spec:
+  entryPoints:
+    - websecure
+  routes:
+    - match: Host(`platform.coreworlds.io`)
+      kind: Rule
+      middlewares:
+        - name: internal-only
+          namespace: platform
+      services:
+        - name: platform-dash
+          namespace: apps
+          port: 80
+  tls:
+    secretName: platform-dash-tls

infra/kubernetes/platform/traefik/kustomization.yaml

@@ -10,5 +10,6 @@ resources:
   - ingressroute-harness.yaml
   - ingressroute-gitea.yaml
   - ingressroute-garage.yaml
+  - ingressroute-platform-dash.yaml
   - certificate-internal.yaml
   - servicemonitor.yaml