Domains are infrastructure, and in v2 infrastructure is the platform owner's
alone (D9). A tenant gets one automatic demo host and nothing else.
- admin_domains.py (owner-only): list every route with its owning app, attach an
extra host, detach with the host typed back as confirmation (audited), re-sync
the router from the database, and read the suggested MCP gateway route.
- domain/platform/rules.py: validate_extra_host. Two shapes only — a single
label under the managed root, or a full custom FQDN when ALLOW_CUSTOM_DOMAINS
is on. A wildcard is refused in both (it would match another tenant's
subdomain), and so are 30 protected platform labels (git, mcp, panel, api...).
Enforced in the router *and* again in the adapter.
- Both router adapters gained routes_fingerprint / list_all_routes /
sync_routes. Re-sync writes and reloads only when the rendered state differs:
a reload drops every in-flight connection on the host, including live demos.
Adapter-level extras, not additions to the frozen DomainRouterPort.
- The member-facing preview-domain routes are owner-only now. They are kept
because the demo host is still created through them at app-creation time.
Tests: 473 API (+58); ruff and mypy clean.
Report: docs/plan/reports/agent-3-phase-4.md
