feat(catalog): index content that lacks range42-style metadata (trainee/_ctf roles, gamification, lxc)

[pparage]

The catalog walker only surfaces entries with meta.json (containers) or meta/main.yml (admin roles). Trainee roles (blue_env, red_env, malware_env), the _ctf Ansible roles, gamification templates, and LXC definitions have no recognized metadata and are invisible in the catalog. Either synthesize entries for role directories lacking meta/main.yml and for gamification manifests, or coordinate adding metadata in range42-catalog so these become browsable.