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/acoustid_lookup.go

@@ -18,17 +18,17 @@ import (
 	"git.fabledsword.com/bvandeusen/minstrel/internal/db/dbq"
 )
 
-// AcoustID lookup worker (M401 #3921).
+// AcoustID lookup worker.
 //
 // A track whose tags carry no recording MBID is invisible to the ListenBrainz
 // similarity arm: it is never a seed and never comes back as a result. This
 // worker fingerprints such tracks and asks AcoustID which recording they are,
-// writing an id only when the answer is unambiguous (D5). The file's own tag
-// always outranks it (D4).
+// writing an id only when the answer is unambiguous (chooseRecording). The
+// file's own tag always outranks it.
 //
-// It never gates anything else (rule 164). With no key, switched off or
-// AcoustID unreachable, it idles and says why through Status; scans and
-// playback do not notice.
+// It never gates anything else. With no key, switched off or AcoustID
+// unreachable, it idles and says why through Status; scans and playback do
+// not notice.
 
 // acoustIDLookupTick is how often the worker looks for work. A settings save
 // starts a pass at once, so this only paces new tracks and retries after an
@@ -187,7 +187,7 @@ func (w *AcoustIDLookupWorker) Run(ctx context.Context) {
 }
 
 // runOnce contains a pass so that nothing it does (an error, a panic) can stop
-// the next one from starting (rule 157).
+// the next one from starting.
 func (w *AcoustIDLookupWorker) runOnce(ctx context.Context) {
 	w.setStatus(func(s *AcoustIDLookupStatus) { s.Running = true })
 	problem := ""
@@ -216,8 +216,8 @@ func (w *AcoustIDLookupWorker) runOnce(ctx context.Context) {
 			"no_match", res.NoMatch, "failed", res.Failed, "inconclusive", res.Inconclusive)
 	}
 	// A recording MBID AcoustID just gave a replacement may be the one its
-	// missing predecessor carried (M485): most of the operator's stale rows
-	// became pairable exactly this way.
+	// missing predecessor carried, which makes the pair foldable
+	// (PairMissingTracks).
 	if res.Matched > 0 && ctx.Err() == nil {
 		if _, err := PairMissingTracks(ctx, w.pool, w.logger); err != nil && ctx.Err() == nil {
 			w.logger.Warn("acoustid lookup: missing-pair pass failed", "err", err)
@@ -322,7 +322,8 @@ func (w *AcoustIDLookupWorker) lookupTrack(
 		if isInconclusive(err) {
 			return "", nil
 		}
-		// fpcalc ran and rejected the file: a verdict, settled until it changes.
+		// fpcalc ran and rejected the file: a verdict, settled until it
+		// changes.
 		return w.store(ctx, row, lookupDecision{state: lookupFailed, detail: err.Error()}), nil
 	}
 	cands, err := w.client.Lookup(ctx, cfg.APIKey, fp.fingerprint, fp.durationSec)
@@ -351,7 +352,7 @@ func (w *AcoustIDLookupWorker) lookupTrack(
 var ErrIdentifyUnavailable = errors.New("acoustid: cannot be asked now")
 
 // IdentifyRecordings asks AcoustID which recordings a file may be, for the
-// duplicate resolver (#6169): every candidate at or above the minimum score,
+// duplicate resolver: every candidate at or above the minimum score,
 // best first. None is an answer: AcoustID does not know the audio. Nothing is
 // stored; the file's own lookup is the worker's.
 func (w *AcoustIDLookupWorker) IdentifyRecordings(ctx context.Context, path string) ([]string, error) {
@@ -432,7 +433,8 @@ type lookupDecision struct {
 	detail     string
 }
 
-// chooseRecording applies D5 to AcoustID's candidates (best score first):
+// chooseRecording picks a recording from AcoustID's candidates (best score
+// first):
 // only recordings at or above minScore count, one of them is a match, and
 // several are told apart by the track's title and length or not at all. A
 // wrong MBID would feed similarity the wrong neighbours, which is worse than