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/genre_test.go

@@ -67,7 +67,7 @@ func utf8Frame(values ...string) []byte {
 	return append([]byte{0x03}, []byte(strings.Join(values, "\x00"))...)
 }
 
-// TestReadID3v2GenreValues_MultiValue is the #2499 regression. dhowden/tag
+// TestReadID3v2GenreValues_MultiValue: dhowden/tag
 // rejoins these values with the empty string, producing "Alternative RockRock";
 // the whole point of our own reader is that they stay separate.
 func TestReadID3v2GenreValues_MultiValue(t *testing.T) {
@@ -88,7 +88,7 @@ func TestReadID3v2GenreValues_MultiValue(t *testing.T) {
 	}
 }
 
-// The operator's worst case: eight values welded into one 70-character token.
+// Eight values that a joining reader would weld into one 70-character token.
 func TestReadID3v2GenreValues_ManyValues(t *testing.T) {
 	values := []string{
 		"Boom Bap", "Downtempo", "Hip Hop", "Instrumental",
@@ -268,7 +268,7 @@ func TestNormaliseGenreValue(t *testing.T) {
 		{"empty", "", nil},
 		{"whitespace only", "   ", nil},
 
-		// The operator's digit soup, one value at a time.
+		// Numeric references, one value at a time.
 		{"bare numeric", "17", []string{"Rock"}},
 		{"bare numeric pop", "13", []string{"Pop"}},
 		{"bare numeric electronic", "52", []string{"Electronic"}},
@@ -426,7 +426,7 @@ func TestTrueUpCasing(t *testing.T) {
 		in   string
 		want string
 	}{
-		// The damage actually present in the operator's library (#2468).
+		// Casing damage tag editors leave.
 		{"edm acronym", "Edm", "EDM"},
 		{"idm acronym", "Idm", "IDM"},
 		{"aor acronym", "Aor", "AOR"},