release: v0.3.6 gitops cutover

- ci: run build jobs on the runner's default linux-amd64 label
- deploy: pin apollo images to 0.3.6 (built+pushed by CI on this tag)

Same app code as v0.3.5; first release deployed via Gitea Actions
(build) + Argo CD (rollout) instead of manual build/import/helm.

deploy/helm/pargar/values-apollo.yaml

@@ -11,7 +11,7 @@ backend:
   image:
     pullPolicy: IfNotPresent
     repository: pargar-backend
-    tag: 0.3.5
+    tag: 0.3.6
   metrics:
     serviceMonitor:
       enabled: true
@@ -41,7 +41,7 @@ frontend:
   image:
     pullPolicy: IfNotPresent
     repository: pargar-frontend
-    tag: 0.3.5
+    tag: 0.3.6
   podDisruptionBudget:
     enabled: false
   replicaCount: 2