The user-facing Search-for-Match / Fix popup runs non-strict MB searches.
That path built a bare "track artist" query with no field scoping, so the
artist was just a free fuzzy term — covers and karaoke whose TITLES contained
the artist name outranked the canonical recording. Reproduced live: searching
"Say You Will" / Foreigner returned cover artists with Foreigner absent, and
"Sweet Child O Mine" / Guns N Roses returned only covers (Presnyakov, PMJ…),
never the Guns N' Roses original.
Keep the track/album side loose (no phrase quotes → diacritic + bracketed-
suffix recall, the reason non-strict exists) but field-scope the artist as
artist:(...) so it constrains. The artist value is Lucene-escaped via
_escape_lucene() — without it, names like "Sunn O)))" or "Anthony Green
(Saosin)" would close the artist:( group early (returning unrelated artists)
or break the query (zero results). Same fix applied to search_release.
Verified against the live MB API: both reporter queries now return the real
artist top-to-bottom; diacritic recall is preserved (artist:(Bjork) folds to
Björk); and paren/?/!-laden artist names produce valid, balanced queries.
Tests pin the constructed query string (no network): non-strict scopes and
escapes the artist while keeping the track loose/unquoted; strict path
unchanged; plus _escape_lucene unit coverage.
