feat: add admin user system with role-based access control

Implement comprehensive admin user system for Kubernetes deployment:

Backend:
- Add isAdmin field to User model for role-based permissions
- Create adminAuth middleware to protect admin-only routes
- Protect 11 routes across rewards, cache, streets, and analytics endpoints
- Update setup-couchdb.js to seed default admin user at deployment

Kubernetes:
- Add ADMIN_EMAIL and ADMIN_PASSWORD to secrets.yaml
- Add ADMIN_EMAIL to configmap.yaml for non-sensitive config
- Create couchdb-init-job.yaml for automated database initialization
- Update secrets.yaml.example with admin user documentation

Frontend:
- Create AdminRoute component for admin-only page protection
- Create comprehensive AdminDashboard with 5 tabs:
  * Overview: Platform statistics and quick actions
  * Users: List, search, manage admin status, delete users
  * Streets: Create, edit, delete streets
  * Rewards: Create, edit, toggle, delete rewards
  * Content: Moderate posts and events
- Add Admin navigation link in Navbar (visible only to admins)
- Integrate admin routes in App.js

Default admin user:
- Email: will@wills-portal.com
- Created automatically by K8s init job at deployment

Routes protected:
- POST/PUT/DELETE /api/rewards (catalog management)
- POST /api/streets (street creation)
- DELETE /api/cache (cache operations)
- GET /api/analytics/* (platform statistics)

🤖 Generated with [Claude Code](https://claude.com/claude-code)

Co-Authored-By: Claude <noreply@anthropic.com>

deploy/k8s/couchdb-init-job.yaml

@@ -0,0 +1,66 @@
+apiVersion: batch/v1
+kind: Job
+metadata:
+  name: couchdb-init
+  labels:
+    app: couchdb-init
+spec:
+  backoffLimit: 3
+  template:
+    metadata:
+      labels:
+        app: couchdb-init
+    spec:
+      imagePullSecrets:
+        - name: regcred
+      initContainers:
+        - name: wait-for-couchdb
+          image: curlimages/curl:8.5.0
+          command:
+            - sh
+            - -c
+            - |
+              until curl -f -s http://adopt-a-street-couchdb:5984/_up > /dev/null 2>&1; do
+                echo "Waiting for CouchDB to be ready..."
+                sleep 3
+              done
+              echo "CouchDB is ready!"
+      containers:
+        - name: couchdb-init
+          image: gitea-http.taildb3494.ts.net/will/adopt-a-street-backend:latest
+          imagePullPolicy: Always
+          command: ["node", "scripts/setup-couchdb.js"]
+          envFrom:
+            - configMapRef:
+                name: adopt-a-street-config
+            - secretRef:
+                name: adopt-a-street-secrets
+          env:
+            - name: COUCHDB_USER
+              valueFrom:
+                secretKeyRef:
+                  name: adopt-a-street-secrets
+                  key: COUCHDB_USER
+            - name: COUCHDB_PASSWORD
+              valueFrom:
+                secretKeyRef:
+                  name: adopt-a-street-secrets
+                  key: COUCHDB_PASSWORD
+            - name: ADMIN_EMAIL
+              valueFrom:
+                secretKeyRef:
+                  name: adopt-a-street-secrets
+                  key: ADMIN_EMAIL
+            - name: ADMIN_PASSWORD
+              valueFrom:
+                secretKeyRef:
+                  name: adopt-a-street-secrets
+                  key: ADMIN_PASSWORD
+          resources:
+            requests:
+              memory: "128Mi"
+              cpu: "100m"
+            limits:
+              memory: "256Mi"
+              cpu: "500m"
+      restartPolicy: Never