cleanup: remove MongoDB dependencies and manifests

- Delete MongoDB StatefulSet and service from Kubernetes
- Remove mongodb-statefulset.yaml manifest file
- Remove mongodb-memory-server from devDependencies
- MongoDB no longer needed after CouchDB migration

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Co-Authored-By: AI Assistant <noreply@ai-assistant.com>

backend/package.json

@@ -39,7 +39,7 @@
     "eslint": "^9.38.0",
     "jest": "^30.2.0",
     "jest-environment-node": "^30.2.0",
-    "mongodb-memory-server": "^10.3.0",
+    
     "socket.io-client": "^4.8.1",
     "supertest": "^7.1.4"
   }

deploy/k8s/mongodb-statefulset.yaml

@@ -1,87 +0,0 @@
-apiVersion: v1
-kind: Service
-metadata:
-  name: adopt-a-street-mongodb
-  labels:
-    app: mongodb
-spec:
-  clusterIP: None  # Headless service for StatefulSet
-  selector:
-    app: mongodb
-  ports:
-    - port: 27017
-      targetPort: 27017
-      name: mongodb
-
----
-apiVersion: apps/v1
-kind: StatefulSet
-metadata:
-  name: adopt-a-street-mongodb
-spec:
-  serviceName: adopt-a-street-mongodb
-  replicas: 1
-  selector:
-    matchLabels:
-      app: mongodb
-  template:
-    metadata:
-      labels:
-        app: mongodb
-    spec:
-      # Place MongoDB on Pi 5 nodes (more RAM)
-      affinity:
-        nodeAffinity:
-          requiredDuringSchedulingIgnoredDuringExecution:
-            nodeSelectorTerms:
-              - matchExpressions:
-                  - key: kubernetes.io/arch
-                    operator: In
-                    values:
-                      - arm64  # Pi 5 architecture
-      containers:
-        - name: mongodb
-          image: mongo:7.0
-          ports:
-            - containerPort: 27017
-              name: mongodb
-          resources:
-            requests:
-              memory: "512Mi"
-              cpu: "250m"
-            limits:
-              memory: "2Gi"
-              cpu: "1000m"
-          volumeMounts:
-            - name: mongodb-data
-              mountPath: /data/db
-          livenessProbe:
-            exec:
-              command:
-                - mongosh
-                - --eval
-                - "db.adminCommand('ping')"
-            initialDelaySeconds: 30
-            periodSeconds: 10
-            timeoutSeconds: 5
-            failureThreshold: 3
-          readinessProbe:
-            exec:
-              command:
-                - mongosh
-                - --eval
-                - "db.adminCommand('ping')"
-            initialDelaySeconds: 5
-            periodSeconds: 10
-            timeoutSeconds: 5
-            failureThreshold: 3
-  volumeClaimTemplates:
-    - metadata:
-        name: mongodb-data
-      spec:
-        accessModes: ["ReadWriteOnce"]
-        resources:
-          requests:
-            storage: 10Gi
-        # Uncomment and set your storage class if needed
-        # storageClassName: local-path