ci: add workspace cargo test job (exclude Slint UI graph)

Run unit/doc tests for the shipping crates workspace on PRs without
compiling qbz-ui. Fix three green-blockers: local playlist schema for
tests, Track.work fixture, and a stale ListenBrainz doctest.

crates/qbz-playlist-import/src/match_qobuz.rs

@@ -327,6 +327,7 @@ mod tests {
             id,
             title: title.to_string(),
             version: None,
+            work: None,
             isrc: None,
             duration: 0,
             track_number: 0,