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/duplicate_survivor_test.go

@@ -42,7 +42,7 @@ func TestProposeSurvivor(t *testing.T) {
 			wantID: "320k", wantReason: "largest file",
 		},
 		{
-			// The #3885 pair: identical audio, sizes equal but for the tags.
+			// Identical audio, sizes equal but for the tags.
 			name: "the longest-standing copy wins when size ties",
 			cands: []SurvivorCandidate{
 				{TrackID: "www-02", FileFormat: "mp3", FileSize: 6_900_000, AddedAt: newer},
@@ -90,9 +90,9 @@ func TestProposeSurvivor_ReasonIsTheDecidingRule(t *testing.T) {
 	}
 }
 
-// M498 #5436: the copy whose tags fit the album outranks every quality rule but
-// lossless, which decides first: a deleted FLAC cannot be recovered, and on
-// 2026-10-20 five went for mp3s whose only edge was a recording MBID. Each tag
+// The copy whose tags fit the album outranks every quality rule but lossless,
+// which decides first: a deleted FLAC cannot be recovered, so it never goes
+// for an mp3 whose only edge is a recording MBID. Each tag
 // fit case is built so file size would choose the other copy.
 func TestProposeSurvivor_LosslessThenTagFit(t *testing.T) {
 	at := time.Date(2025, 1, 1, 0, 0, 0, 0, time.UTC)