fix: revert image names to match service.mk directory-derived names

service.mk builds homelab/<dirname>:latest so manifests must match:
- homelab/api:latest (finance/services/api)
- homelab/users:latest (auth/services/users)
- homelab/gateway:latest (auth/services/gateway)

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

apps/auth/services/gateway/k8s/deployment.yaml

@@ -17,7 +17,7 @@ spec:
     spec:
       containers:
         - name: gateway
-          image: homelab/auth-gateway:latest
+          image: homelab/gateway:latest
           imagePullPolicy: IfNotPresent
           ports:
             - name: http

apps/auth/services/users/k8s/deployment.yaml

@@ -17,7 +17,7 @@ spec:
     spec:
       containers:
         - name: users
-          image: homelab/auth-users:latest
+          image: homelab/users:latest
           imagePullPolicy: IfNotPresent
           ports:
             - name: http

apps/finance/services/api/k8s/deployment.yaml

@@ -17,7 +17,7 @@ spec:
     spec:
       containers:
         - name: api
-          image: homelab/finance-api:latest
+          image: homelab/api:latest
           imagePullPolicy: IfNotPresent
           ports:
             - name: http