flake: add kanidm to devshell

Add kanidm_1_8 CLI for administering the Kanidm server.

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

flake.nix

@@ -207,6 +207,7 @@
               pkgs.ansible
               pkgs.opentofu
               pkgs.openbao
+              pkgs.kanidm_1_8
               (pkgs.callPackage ./scripts/create-host { })
               homelab-deploy.packages.${pkgs.system}.default
             ];