Create SearchIndex in NewExploreService, start background build in
SetContext (on app startup). Search() now has 6 phases:
Phase 0: query local FTS5 index (instant, no API calls)
Phase 1: concurrent MB search
Phase 2: LB popularity boost
Phase 3: cross-reference artist discographies
Phase 4: merge index hits (prepend new entries, dedup by MBID)
Phase 5: filter and cap
Index hits for release groups/recordings not already in MB results
are prepended so popular albums surface even when MB search can't
find them. scalePopularity() maps raw listen counts to 0-100 scores
via log scaling for compatibility with the blended score system.
yonlu
cf40909313