### `wai.live.room`: room descriptors, room grants and the room verifier

- **The extension** ([live-rooms](extensions/live-rooms.md)) registers the record
  `wai.live.room`. A room is fixed by a signed descriptor, `WRD1`, whose digest is the
  room id every `WEV1` event names: its authority, its clock and `t0`, the roles a
  principal may hold (publish per media kind, subscribe up to a layer, the event kinds it
  may send, and the moderate, direct, compose and record powers), its limits and event
  ceiling, the slots several publishers may stand behind, its publish profiles, its
  review policy and its recording policy with a region pin.
- **Grants.** A principal takes part under a signed room grant, `WRG1`: its role and
  capabilities, a window of at most fourteen days, its delivery origins, a single-use
  nonce, a viewer id, the `WEP1` event policy of live-events §5 it is held to, its joule
  and funds ceilings, the profiles it publishes with, and at most 1 KB of composition
  attributes. A grant is exchanged for one chained to it at a tick of the room clock,
  recorded as the `grant_exchange` lifecycle event, and revoked through the authority's
  key log: the head's `revoked_modules` lists revoked grants and viewers, and the
  authority's key holds the new authority `live/room` (jwp-receipts §7.2, §7.5, §7.6).
- **Tracks, slots and profiles.** A track is named by the MOQT namespace tuple (room,
  principal or slot, media kind) and its layer. A slot is a virtual track: a publisher of
  higher precedence takes it over with no new session, and a standby takes it on failover
  under the slot's rule. The lifecycle kinds' `detail` is defined. The publish profiles
  `speech`, `music`, `screen`, `camera-720` and `camera-1080` fix codecs, layers and
  limits as data.
- **Room verification.** Given a descriptor, grants, a key-log head and every principal's
  chain, a verifier merges the chains by room clock, verifies each event with the
  live-events verifier under the policy of the grant in effect at its `t`, and replays the
  lifecycle into room state; each refusal has a named reason (§11).
- **Bindings**, as tables: the Common Access Token's claims (CTA-5007-B), the `moqt` claim
  of `draft-ietf-moq-c4m-01` (whose scopes the reference derives from each grant), URI
  Signing (RFC 9246) and Privacy Pass (`draft-ietf-moq-privacy-pass-auth-03`). No CAT
  encoding: the crate has no CBOR.
- **Reference and corpus.** `wai-rs` feature `live_room` (`src/live_room.rs`);
  `live-conformance/rooms/`, written from fixed seeds by `wai_live_room_vectors`, and
  checked by `tests/live_room.rs` and by `live-conformance/live_rooms_verify.py`, a second
  implementation that shares no code with `wai-rs`. The registry lists the record and its
  magics (`WRD1`, `WRG1`).

