spacedb-access 0.5.2

SpaceDB Layer 5 — identity & access: signed, scoped, expiring, revocable capabilities (ECDSA P-256 / ES256) that gate every read/write/compute. Inaccessible by default, accessible by mID-gated consent. The DID directory is a seam MATA implements over IAMHUMAN. Phase 1 SpaceDB Mission, M5.