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.

apps/platform-dash/k8s/base/deployment.yaml

@@ -0,0 +1,59 @@
+apiVersion: apps/v1
+kind: Deployment
+metadata:
+  name: platform-dash
+  namespace: apps
+  labels:
+    app: platform-dash
+spec:
+  replicas: 1
+  selector:
+    matchLabels:
+      app: platform-dash
+  template:
+    metadata:
+      labels:
+        app: platform-dash
+    spec:
+      imagePullSecrets:
+        - name: gitea-pull-secret
+      containers:
+        - name: platform-dash
+          image: gitea.coreworlds.io/lazorgurl/homelab-platform-dash:latest
+          ports:
+            - containerPort: 3200
+          env:
+            - name: S3_ENDPOINT
+              value: "http://garage.platform.svc:3900"
+            - name: S3_REGION
+              value: "garage"
+            - name: S3_BUCKET
+              value: "artifacts"
+            - name: S3_ACCESS_KEY_ID
+              valueFrom:
+                secretKeyRef:
+                  name: platform-dash-s3
+                  key: access-key-id
+            - name: S3_SECRET_ACCESS_KEY
+              valueFrom:
+                secretKeyRef:
+                  name: platform-dash-s3
+                  key: secret-access-key
+          resources:
+            requests:
+              memory: 128Mi
+              cpu: 100m
+            limits:
+              memory: 256Mi
+          readinessProbe:
+            httpGet:
+              path: /
+              port: 3200
+            initialDelaySeconds: 5
+            periodSeconds: 10
+          livenessProbe:
+            httpGet:
+              path: /
+              port: 3200
+            initialDelaySeconds: 15
+            periodSeconds: 20