fix(ci): remove kubernetes-deploy workflow that leaked secrets to logs

The workflow ran on every push to every branch and deployed nothing.
It echoed the raw Vault login response, the Kanidm API token response
and the OIDC token response to the job log, dumped the environment,
and configured kubectl with --insecure-skip-tls-verify.

Deployment is handled by gitops-update.yaml. Docs updated to describe
that flow; T1 marked done in the cleanup task list.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

docs/by-claude-opus/README.md

@@ -182,7 +182,7 @@ fuj-management/
 │
 ├── .gitea/workflows/
 │   ├── build.yaml                  # CI: build + push Docker image
-│   └── kubernetes-deploy.yaml      # CD: deploy to K8s cluster
+│   └── gitops-update.yaml          # CD: open image-update PR in home-kubernetes
 │
 ├── .secret/                        # (gitignored) API credentials
 ├── docs/                           # Project documentation