Sync host lists with flake.nix and add CLAUDE.md

Remove the nonexistent kuma host and add the missing linode-minimal
host across README, AGENTS.md, docs, and CI eval workflows so they
match flake.nix's nixosConfigurations. Also add CLAUDE.md with
architecture/safety guidance for future Claude Code sessions.

Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com>

README.md

@@ -11,11 +11,11 @@ This flake currently defines:
 | --- | --- |
 | `nixos` | Main NixOS workstation / Cinnamon desktop |
 | `docker` | Docker host for the main container stack |
-| `kuma` | Docker-enabled Uptime Kuma style host |
 | `server` | Storage, NFS, backup, and monitoring exporter host |
 | `nix-cache` | Local Nix binary cache and remote builder |
 | `nix-minimal` | Minimal NixOS host profile with SSHFS tooling |
 | `pxe-boot` | HTTP/iPXE boot asset host |
+| `linode-minimal` | Minimal NixOS host profile for Linode VPS instances |
 
 List hosts with: