feat: migrate CI/CD from GHCR to local Harbor registry

- Makefile: GHCR -> registry.celestium.life/stonks-oracle
- GitHub Actions: login to Harbor, use HARBOR_PASSWORD secret
- infra/k8s/*.yaml: all image refs -> registry.celestium.life
- inttest pipeline: remove GHCR pull secret (local registry, no auth)
- Steering docs: update registry/git endpoints

infra/k8s/parser-worker.yaml

@@ -28,7 +28,7 @@ spec:
           type: RuntimeDefault
       containers:
         - name: parser-worker
-          image: ghcr.io/celesrenata/stonks-oracle/parser:latest
+          image: registry.celestium.life/stonks-oracle/parser:latest
           imagePullPolicy: Always
           securityContext:
             allowPrivilegeEscalation: false