fix: production API URL, k8s single replica, health probes

- Change API_URL default from localhost:4000 to empty string (relative URLs)
- Set VITE_API_URL="" explicitly in Dockerfile frontend build stage
- Reduce k8s replicas to 1 (SQLite + ReadWriteOnce PVC)
- Add liveness and readiness probes targeting /health endpoint

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

k8s.yaml

@@ -22,7 +22,7 @@ spec:
   selector:
     matchLabels:
       app: awards
-  replicas: 2
+  replicas: 1
   template:
     metadata:
       labels:
@@ -77,6 +77,22 @@ spec:
             limits:
               memory: "512Mi"
               cpu: "500m"
+          livenessProbe:
+            httpGet:
+              path: /health
+              port: 4000
+            initialDelaySeconds: 10
+            periodSeconds: 30
+            timeoutSeconds: 3
+            failureThreshold: 3
+          readinessProbe:
+            httpGet:
+              path: /health
+              port: 4000
+            initialDelaySeconds: 5
+            periodSeconds: 10
+            timeoutSeconds: 3
+            failureThreshold: 3
       volumes:
         - name: data
           persistentVolumeClaim: