Implements ADR-0001. kinds.py pins the allocations; events.py has pure
builders (30402 listing, 30078 encrypted reservation, 31923 blocked-range
calendar, 22001 availability response); service.py signs/encrypts via
resolve_signer (spirekeeper hybrid pattern — no nsec at rest) and sketches
publish + inbound subscription. Relay plumbing marked TODO(relay).
Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_019VUQCfdqiLSsFS2jcGnaFD
