Clean up stale multi-level mDNS remnants across the workspace

[mairas]

Context

The multi-level mDNS subdomain approach (cockpit.<host>.local, etc.) was retired in favor of path-based routing and the multi-hostname plan (already implemented in halos-core-containers). Two pockets of stale references survive and actively mislead readers — both human and AI — into reasoning about a feature that no longer exists.

This was surfaced during a design discussion where an AI assistant repeatedly built wrong mental models from the stale code before realizing the deployed system worked differently. The cost of leaving these in place compounds with every reader.

Scope

1. Workspace AGENTS.md (this repo)

AGENTS.md:79 lists halos-mdns-publisher/ in the Structure section, even though that repo is archived. Remove the line.

Possibly worth a wider audit of the Structure section vs. ./run's REPOS map — they diverge (Structure lists 19 entries, REPOS lists 11). Out of scope for this issue; flagged for a follow-up if it bites someone.

2. container-packaging-tools — stale halos-core-containers/ subtree

Tracked separately: halos-org/container-packaging-tools#204

The container-packaging-tools/halos-core-containers/ subtree contains pre-multi-hostname-plan templates (Traefik Host(cockpit.${HALOS_DOMAIN}) rules, wildcard *.${HALOS_DOMAIN} SAN, halos.subdomain label emission) that no longer match the active halos-core-containers repo. Confirmed container-packaging-tools does not regenerate halos-core-containers — it only references it as a version constraint — so the subtree is dead fixture, not a generation source.

Verification done

• git remote -v → workspace is halos-org/halos
• ./run REPOS map — no halos-mdns-publisher entry (already clean)
• grep -rn 'halos.subdomain\|cockpit\.\${HALOS\|\*\.\${HALOS_DOMAIN}' halos-core-containers/ (real repo, excluding debian/ build output) — zero results, fully clean
• Multi-hostname plan implementation confirmed: halos-core-containers/prestart.sh:35 calls halos_load_hostnames, SAN list at :106-117 is halos_all_hostnames-driven (no wildcard), Cockpit routing at :163-214 is path-based (/cockpit/ redirects to :9090)

Out of scope

• Wider AGENTS.md/REPOS divergence audit
• Refactoring or improvements to container-packaging-tools's real surface area
• Anything in archived repos themselves

[mairas]

Both scoped items merged:

• Workspace AGENTS.md (this repo): halos-mdns-publisher/ removed from AGENTS.md:79 via docs: remove archived halos-mdns-publisher from structure lists #112. The parallel stale line in README.md:266 was caught and removed in the same PR.
• container-packaging-tools: dead subdomain routing path removed via refactor: remove dead subdomain routing path container-packaging-tools#205 (closes Remove stale halos-core-containers/ subtree container-packaging-tools#204).

One nuance on the c-p-t side: the issue framed it as "subtree cleanup," but git log --all -- halos-core-containers/ in c-p-t is empty — that path was never tracked, it's just a separately cloned hatlabs/halos-core-containers working tree some checkouts carry locally. The substantive cleanup was the code-path removal in c-p-t itself (dead generate_traefik_labels, dead subdomain schema field, dead OIDC subdomain prefixing), all done in #205 with zero behavior change.

The out-of-scope follow-up flagged in the original issue (workspace AGENTS.md Structure list vs ./run REPOS map divergence — 19 entries vs 11) remains untouched; file a new issue if and when it bites.