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/fingerprint_test.go

@@ -122,7 +122,8 @@ func TestFpcalcLookupArgs_RequestCompressedOutput(t *testing.T) {
 }
 
 func TestParseStreamHash(t *testing.T) {
-	// The real value ffmpeg printed for both files of the #3885 pair.
+	// The real value ffmpeg printed for two copies of one MP3 differing only
+	// in their ID3.
 	const www = "24e2daa3b4a534ff1a8d1a76f67810205869daf89f728d83a16625da4d28a18e"
 
 	got, err := parseStreamHash([]byte("SHA256=" + www + "\n"))
@@ -146,7 +147,8 @@ func TestParseStreamHash(t *testing.T) {
 	}
 }
 
-// followedBy reports whether flag appears in args immediately followed by value.
+// followedBy reports whether flag appears in args immediately followed by
+// value.
 func followedBy(args []string, flag, value string) bool {
 	for i := 0; i+1 < len(args); i++ {
 		if args[i] == flag && args[i+1] == value {
@@ -255,7 +257,7 @@ func TestFingerprintResult_InconclusiveIfEitherHalfIs(t *testing.T) {
 }
 
 // fpcalc 1.5.1 exits 3 with "(End of file)" on every file shorter than the
-// span asked for (#6178). That print covers the whole file and is kept; a file
+// span asked for. That print covers the whole file and is kept; a file
 // whose declared length runs past the span stopped early, and is not.
 func TestFpcalcReadToEnd(t *testing.T) {
 	eof := []byte("ERROR: Error decoding audio frame (End of file)")