docs: library comments say what the scanner and resolver do, not how they came to be (#6277)

Rewrites the internal/library comment blocks to rule 32. Task, milestone,
decision and rule ids are gone; the incidents behind them are restated as
the constraint they left (why a file is deleted before its row, why the
missing mark is a mark, why duplicates block on duration). Counts and
album names from one library are dropped from production comments; test
comments keep the names their fixtures use. The tagReadVersion log keeps
each version's before and after, without the measurements.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

internal/library/notify.go

@@ -10,7 +10,7 @@ import (
 	"git.fabledsword.com/bvandeusen/minstrel/internal/notifications"
 )
 
-// Package-level notifier for library-health notices to admins (M489): a
+// Package-level notifier for library-health notices to admins: a
 // scan that failed, tracks gone missing, new duplicates. Set once at startup
 // beside SetEventBus, for the same reason the bus is package-level. Nil, as in
 // tests that never set it, means nobody is told.
@@ -49,9 +49,9 @@ func TrackLabel(artist, title string) string {
 }
 
 // notifyStillMissing tells admins which of the tracks a scan marked missing
-// are still gone after it adopted moves and folded replacements (M542). A
-// marked track the scan healed is not news: reporting it is what made a
-// quality upgrade read as lost music.
+// are still gone after it adopted moves and folded replacements. A marked
+// track the scan healed is not news: reporting it would make a quality
+// upgrade read as lost music.
 func (s *Scanner) notifyStillMissing(ctx context.Context, marked []pgtype.UUID) {
 	if len(marked) == 0 || ctx.Err() != nil {
 		return