v2.8.0

Adds a universal Look Up screen and restricts management actions to resource owners.

- New "Look Up" entry in More to find any sr.ht resource by name or ID
- Supports users, Git and Hg repositories, mailing lists, trackers, and build jobs
- Results open directly in the matching detail view
- Repository settings gear now only visible to the repository owner
- Tracker management menu and ticket assignment now only visible to the tracker owner
- GraphQL errors are now detected before typed response decoding, fixing silent failures
- Fix thread navigation from mailing list detail when opened via Look Up