feat: add Kubernetes Kustomize deployment manifests

Add k8s/base/ directory with Kustomize manifests for deploying
the scrum-manager application to Kubernetes:

- Namespace (scrum-manager)
- MySQL: Deployment, Service, PVC, Secret
- Backend: Deployment (2 replicas) with init container, Service
- Frontend: Deployment (2 replicas), Service (NodePort), ConfigMap (nginx.conf)

All deployments include resource requests/limits, liveness/readiness
probes, and proper label selectors.

k8s/base/frontend/configmap.yaml

@@ -0,0 +1,31 @@
+apiVersion: v1
+kind: ConfigMap
+metadata:
+  name: frontend-nginx-config
+  labels:
+    app.kubernetes.io/name: frontend
+    app.kubernetes.io/component: web
+data:
+  default.conf: |
+    server {
+        listen 80;
+        server_name localhost;
+
+        root /usr/share/nginx/html;
+        index index.html;
+
+        # Serve static files
+        location / {
+            try_files $uri $uri/ /index.html;
+        }
+
+        # Proxy API requests to backend service
+        location /api/ {
+            proxy_pass http://backend:3001;
+            proxy_http_version 1.1;
+            proxy_set_header Upgrade $http_upgrade;
+            proxy_set_header Connection 'upgrade';
+            proxy_set_header Host $host;
+            proxy_cache_bypass $http_upgrade;
+        }
+    }

k8s/base/frontend/deployment.yaml

@@ -0,0 +1,58 @@
+apiVersion: apps/v1
+kind: Deployment
+metadata:
+  name: frontend
+  labels:
+    app.kubernetes.io/name: frontend
+    app.kubernetes.io/component: web
+spec:
+  replicas: 2
+  selector:
+    matchLabels:
+      app.kubernetes.io/name: frontend
+      app.kubernetes.io/component: web
+  template:
+    metadata:
+      labels:
+        app.kubernetes.io/name: frontend
+        app.kubernetes.io/component: web
+    spec:
+      containers:
+        - name: frontend
+          image: scrum-frontend:latest
+          imagePullPolicy: IfNotPresent
+          ports:
+            - containerPort: 80
+              name: http
+          volumeMounts:
+            - name: nginx-config
+              mountPath: /etc/nginx/conf.d/default.conf
+              subPath: default.conf
+              readOnly: true
+          resources:
+            requests:
+              cpu: 50m
+              memory: 64Mi
+            limits:
+              cpu: 200m
+              memory: 128Mi
+          livenessProbe:
+            httpGet:
+              path: /
+              port: http
+            initialDelaySeconds: 10
+            periodSeconds: 10
+            timeoutSeconds: 3
+            failureThreshold: 3
+          readinessProbe:
+            httpGet:
+              path: /
+              port: http
+            initialDelaySeconds: 5
+            periodSeconds: 5
+            timeoutSeconds: 3
+            failureThreshold: 3
+      volumes:
+        - name: nginx-config
+          configMap:
+            name: frontend-nginx-config

k8s/base/frontend/service.yaml

@@ -0,0 +1,17 @@
+apiVersion: v1
+kind: Service
+metadata:
+  name: frontend
+  labels:
+    app.kubernetes.io/name: frontend
+    app.kubernetes.io/component: web
+spec:
+  type: NodePort
+  ports:
+    - port: 80
+      targetPort: 80
+      protocol: TCP
+      name: http
+  selector:
+    app.kubernetes.io/name: frontend
+    app.kubernetes.io/component: web