fix: update app labels to use correct Kubernetes naming

Refactor Kubernetes resource definitions to replace the label  
"app" with "app.kubernetes.io/name" for the dancefinder-app.  
This change enhances consistency with Kubernetes best practices  
and improves clarity in resource labeling across deployments,  
services, and autoscalers.

k8s/autoscale-prod.yaml

@@ -2,7 +2,7 @@ apiVersion: autoscaling/v2
 kind: HorizontalPodAutoscaler
 metadata:
   labels:
-    app: dancefinder-app
+    app.kubernetes.io/name: dancefinder-app
   name: dancefinder-app
 spec:
   scaleTargetRef:

k8s/deploy.yaml

@@ -3,7 +3,7 @@ kind: Deployment
 metadata:
   name: dancefinder-app
   labels:
-    app: dancefinder-app
+    app.kubernetes.io/name: dancefinder-app
   annotations:
     kubernetes.io/change-cause: "${TIMESTAMP} Deployed commit id: ${COMMIT}"
 spec:
@@ -16,11 +16,11 @@ spec:
   minReadySeconds: 30
   selector:
     matchLabels:
-      app: dancefinder-app
+      app.kubernetes.io/name: dancefinder-app
   template:
     metadata:
       labels:
-        app: dancefinder-app
+        app.kubernetes.io/name: dancefinder-app
     spec:
       affinity:
         podAntiAffinity:
@@ -29,7 +29,7 @@ spec:
             podAffinityTerm:
               labelSelector:
                 matchExpressions:
-                - key: "app"
+                - key: "app.kubernetes.io/name"
                   operator: In
                   values:
                   - dancefinder-app
@@ -63,11 +63,11 @@ kind: Service
 metadata:
   name: dancefinder-app
   labels:
-    app: dancefinder-app
+    app.kubernetes.io/name: dancefinder-app
 spec:
   type: NodePort
   selector:
-    app: dancefinder-app
+    app.kubernetes.io/name: dancefinder-app
   ports:
   - port: 80
     targetPort: 80