Pubky auth approval does not show the relay origin on Android #1505

iOS shows where a Pubky authorization will be delivered; Android does not.

On iOS, PubkyAuthRequest.relayOrigin (Bitkit/Models/PubkyAuthRequest.swift:190) takes the scheme, host and port of the request's relay URL. PubkyAuthApprovalSheet then shows it in a relay section (pubky_auth__authorization_relay, PubkyAuthRelayOrigin) and in the watch-only intro (pubky_auth__watch_only_intro_relay). It was added in bitkit-ios 69025cdb ("fix: route gifts and identify auth relay").

Android's PubkyAuthApprovalSheet has neither. Approving sends the grant to the relay without telling the user which origin receives it. A user cannot tell that a request from a familiar app will deliver its grant to an unrelated host.

Noticed while reviewing #1494, which edits the Android approval sheet but not this part.

Steps

1. Open pubkyauth://signin_grant?caps=/pub/paykit/:rw&relay=https://relay.example.com/link&secret=… on both platforms.
2. iOS shows "relay.example.com" in the authorization sheet. Android does not mention the relay.

Expected: port the relay-origin section and the watch-only intro wording to Android, with the same PubkyAuthRelayOrigin test tag, and port the matching journey step if iOS has one.