ci: deploy :latest with rollout restart, single replica

Drop the sha-pinned overlay and automatic rollback. The deployment now
runs 1 replica with imagePullPolicy Always, and CI restarts it after
apply so the new :latest image is pulled.

Co-Authored-By: Claude Opus 5.5 (1M context) <noreply@anthropic.com>

k8s/deployment.yaml

@@ -5,7 +5,7 @@ metadata:
   labels:
     app: jesseinit-portfolio
 spec:
-  replicas: 2
+  replicas: 1
   revisionHistoryLimit: 5
   strategy:
     type: RollingUpdate
@@ -23,7 +23,7 @@ spec:
       containers:
       - name: portfolio
         image: jesseinit-portfolio:latest
-        imagePullPolicy: IfNotPresent
+        imagePullPolicy: Always
         ports:
         - containerPort: 3000
           name: http