fix container port: nginx listens on 80, not 8080

The unified image uses nginx on port 80 as the entrypoint, which
reverse-proxies to the Go backend on 127.0.0.1:8080 internally.
K8s was exposing 8080 directly, bypassing nginx entirely.

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

k8s/ingress.yaml

@@ -43,4 +43,4 @@ spec:
           service:
             name: switchboard${DEPLOY_SUFFIX}
             port:
-              number: 8080
+              number: 80

k8s/switchboard.yaml

@@ -52,7 +52,7 @@ spec:
         image: ${IMAGE}:${IMAGE_TAG}
         imagePullPolicy: Always
         ports:
-        - containerPort: 8080
+        - containerPort: 80
           name: http
         env:
         - name: ENVIRONMENT
@@ -168,7 +168,7 @@ spec:
         readinessProbe:
           httpGet:
             path: ${BASE_PATH}/health
-            port: 8080
+            port: 80
           initialDelaySeconds: 5
           periodSeconds: 10
           timeoutSeconds: 3
@@ -176,7 +176,7 @@ spec:
         livenessProbe:
           httpGet:
             path: ${BASE_PATH}/health
-            port: 8080
+            port: 80
           initialDelaySeconds: 10
           periodSeconds: 30
           timeoutSeconds: 5
@@ -201,6 +201,6 @@ spec:
     env: ${ENVIRONMENT}
   ports:
   - protocol: TCP
-    port: 8080
-    targetPort: 8080
+    port: 80
+    targetPort: 80
     name: http