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/mbids_test.go

@@ -170,7 +170,7 @@ func TestCleanMBID_OnlyNULReturnsEmpty(t *testing.T) {
 	}
 }
 
-// #5241: the release-group id is read beside the release id, from each
+// The release-group id is read beside the release id, from each
 // format's own key, and the two are never confused.
 func TestExtractReleaseGroupMBID(t *testing.T) {
 	cases := []struct {
@@ -207,7 +207,7 @@ func TestExtractReleaseGroupMBID(t *testing.T) {
 	}
 }
 
-// #5637: each format's recording id lands in Recording, and the release-track
+// Each format's recording id lands in Recording, and the release-track
 // id never does. Picard calls the recording MUSICBRAINZ_TRACKID in Vorbis
 // comments, the name mbz gives the release track.
 func TestReadTagMBIDs_Recording(t *testing.T) {
@@ -243,8 +243,7 @@ func TestReadTagMBIDs_Recording(t *testing.T) {
 	}
 }
 
-// A Vorbis TRACKNUMBER of "3/20", as Minstrel's importer wrote it, is track 3
-// (#6171): dhowden/tag reads it as 0.
+// A Vorbis TRACKNUMBER of "3/20" is track 3: dhowden/tag reads it as 0.
 func TestReadTrackAndDisc(t *testing.T) {
 	for _, tc := range []struct {
 		name        string