feat: add complete Kubernetes deployment infrastructure

Add production-ready deployment configuration for Raspberry Pi cluster with comprehensive documentation and automation scripts.

Kubernetes Manifests (deploy/k8s/):
- namespace.yaml - Dedicated namespace for the application
- configmap.yaml - Environment configuration (MongoDB URI, ports, URLs)
- secrets.yaml.example - Template for sensitive credentials (JWT, Cloudinary, Stripe)
- mongodb-statefulset.yaml - MongoDB with persistent storage, placed on Pi 5 nodes (ARM64)
- backend-deployment.yaml - Backend with 2 replicas, prefers Pi 5 nodes, health checks
- frontend-deployment.yaml - Frontend with 2 replicas, can run on any node, nginx-based
- ingress.yaml - Traefik/NGINX ingress for API, Socket.IO, and frontend routing

Docker Configuration:
- backend/Dockerfile - Multi-stage build for ARM64/ARMv7 with health checks
- backend/.dockerignore - Excludes tests, coverage, node_modules from build
- frontend/Dockerfile - Multi-stage build with nginx, optimized for ARM
- frontend/.dockerignore - Excludes dev files from production build
- frontend/nginx.conf - Production nginx config with gzip, caching, React Router support

Resource Optimization for Pi Cluster:
- MongoDB: 512Mi-2Gi RAM, 250m-1000m CPU (Pi 5 only, ARM64 affinity)
- Backend: 256Mi-512Mi RAM, 100m-500m CPU (prefers Pi 5, ARM64)
- Frontend: 64Mi-128Mi RAM, 50m-200m CPU (any node, lightweight)
- Total: ~3.5GB RAM minimum, perfect for 2x Pi 5 (8GB) + 1x Pi 3B+ (1GB)

Automation Scripts (deploy/scripts/):
- build.sh - Build multi-arch images (ARM64/ARMv7) and push to registry
- deploy.sh - Deploy all Kubernetes resources with health checks and status reporting
- Both scripts include error handling, color output, and comprehensive logging

Documentation (deploy/README.md):
- Complete deployment guide with prerequisites
- Step-by-step instructions for building and deploying
- Verification commands and troubleshooting guide
- Scaling, updating, and rollback procedures
- Resource monitoring and cleanup instructions
- Security best practices and performance optimization tips

Health Endpoints:
- Backend: GET /api/health (status, uptime, MongoDB connection)
- Frontend: GET /health (nginx health check)
- Used by Kubernetes liveness and readiness probes

Key Features:
- Multi-architecture support (ARM64 for Pi 5, ARMv7 for Pi 3B+)
- NodeAffinity places heavy workloads (MongoDB, backend) on Pi 5 nodes
- Persistent storage for MongoDB (10Gi PVC)
- Horizontal pod autoscaling ready
- Zero-downtime deployments with rolling updates
- Comprehensive health monitoring
- Production-grade nginx with security headers
- Ingress routing for API, WebSocket, and static assets

Security:
- Secrets management with Kubernetes Secrets
- secrets.yaml excluded from Git (.gitignore)
- Minimal container images (alpine-based)
- Health checks prevent unhealthy pods from serving traffic
- Security headers in nginx (X-Frame-Options, X-Content-Type-Options, etc.)

Usage:
1. Build images: ./deploy/scripts/build.sh
2. Configure secrets: cp deploy/k8s/secrets.yaml.example deploy/k8s/secrets.yaml
3. Deploy: ./deploy/scripts/deploy.sh
4. Monitor: kubectl get all -n adopt-a-street

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

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

deploy/k8s/mongodb-statefulset.yaml

@@ -0,0 +1,89 @@
+apiVersion: v1
+kind: Service
+metadata:
+  name: adopt-a-street-mongodb
+  namespace: adopt-a-street
+  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
+  namespace: adopt-a-street
+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