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/microsandbox/install.md

@@ -0,0 +1,14 @@
+```bash
+virt-install \
+  --name microsandbox \
+  --ram 8192\
+  --vcpus 4 \
+  --cpu host-passthrough \
+  --os-variant ubuntu24.04 \
+  --disk path=/srv/vms/microsandbox.qcow2,size=100,format=qcow2,bus=virtio \
+  --network bridge=br0,model=virtio \
+  --graphics none \
+  --console pty,target_type=serial \
+  --location /srv/vms/isos/ubuntu-24.04.3-live-server-amd64.iso,kernel=casper/vmlinuz,initrd=casper/initrd \
+  --extra-args 'console=ttyS0,115200n8'
+```