Nostr-native room rentals (Airbnb-style) for the castle. Establishes the
extension manifest, license, README with the design overview, and static
+ template placeholders. No booking logic yet — subsequent commits build
the model, schema, arbiter, Nostr layer, API, tasks, and wiring bottom-up.
Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_019VUQCfdqiLSsFS2jcGnaFD
