feat(nestsClient): NIP-98 auth + nests room-info client

Phase 3a of the Clubhouse/nests integration. Adds a new KMP module
`nestsClient` (Android + JVM targets) that owns the HTTP control plane
for talking to a nests audio-room backend. No transport/audio yet —
that arrives in 3b with WebTransport + MoQ.

Surface:
- `NestsAuth.header(signer, url, method)` signs a kind 27235 event via
  Quartz's existing HTTPAuthorizationEvent and returns a ready-to-use
  `Authorization: Nostr <base64>` header value.
- `NestsRoomInfo` data class + tolerant JSON parser (ignores unknown
  fields so newer nests server revisions don't break older clients).
- `NestsClient.resolveRoom(serviceBase, roomId, signer)` calls
  `<serviceBase>/<roomId>` with the signed NIP-98 header and returns
  the MoQ endpoint + token the audio layer will need.
- `OkHttpNestsClient` (jvmAndroid) is the default implementation
  shared between Android and desktop JVM.

Tests:
- `NestsRoomInfoTest` (commonTest) covers full/minimal payloads,
  unknown-field tolerance, missing-endpoint rejection, and URL
  construction edge cases.
- `NestsAuthTest` (jvmTest) signs a real 27235 event, decodes the
  base64 back through Quartz's JacksonMapper, and asserts the
  signature verifies and the url+method tags bind correctly.

https://claude.ai/code/session_013nVLALALKaHVgHm9u5Cg8D

settings.gradle

@@ -36,5 +36,6 @@ include ':benchmark'
 include ':quartz'
 include ':commons'
 include ':ammolite'
+include ':nestsClient'
 include ':desktopApp'
 include ':cli'