misc: zot registry, k8s OIDC, server configs, sandbox experiments, and notes

- docker-30/zot: add Zot OCI registry with on-demand sync to docker.io,
  registry.k8s.io, ghcr.io, quay.io
- kubernetes-kvm-terraform: wire Kanidm OIDC via structured
  AuthenticationConfiguration; add reference apiserver manifest and
  join-node-02 helper
- servers: reorganize shadow/ under servers/, add saint vhost config and
  utility-101 VM definition, add shadow hrajfrisbee.cz vhost and
  storage-23 notes
- experiments: add notes and configs for e2b dev VM, kata + firecracker
  on kube, microsandbox, orb-stack k3s (terraform + cloud-init), rke2
- vms/docker: document tailscale + node-exporter setup
- blog: stub post on Gateway API
- chore: gitignore tmp/, smtp_password, and the two local-only
  credential caches; add per-project .claude/settings.json

Co-Authored-By: Claude Opus 4.7 <noreply@anthropic.com>

experiments/orb-stack/stacks/k3s/cloud-init-worker.yaml

@@ -0,0 +1,9 @@
+#cloud-config
+merge_how:
+  - name: list
+    settings: [append]
+  - name: dict
+    settings: [recurse_array]
+
+runcmd:
+  - curl -sfL https://get.k3s.io | INSTALL_K3S_EXEC="agent" K3S_URL="https://${cp_ip}:6443" K3S_TOKEN="${join_token}" sh -