Exercise subdomain resolution (base-domain and generic hosts, unknown slug, www, port stripping, contextvar cleanup), slug derivation and uniqueness, the require_current_club/current() context helpers, and ClubScopedModel save/for_club/current via Season. Add a with_club test helper. Tenancy modules reach 100% coverage. Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>