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_settings.go

@@ -12,10 +12,10 @@ import (
 	"git.fabledsword.com/bvandeusen/minstrel/internal/db/dbq"
 )
 
-// Fingerprinting settings (M400 #3913).
+// Fingerprinting settings.
 //
-// Rule 25: what an operator might tune lives in the database and changes without
-// a restart. One service instance is shared by the scanner, the backfill, the
+// What an admin might tune lives in the database and changes without a
+// restart. One service instance is shared by the scanner, the backfill, the
 // duplicate sweep and the admin API, so a save reaches all of them at once.
 //
 // The length is the dangerous knob: chromaprints taken at two lengths cannot be
@@ -29,8 +29,9 @@ import (
 // Bounds for each setting, mirrored by migration 0061's CHECKs.
 const (
 	// Below 30s a print has too few items to align at the matcher's larger
-	// offsets and still overlap by minOverlapItems. Above 600s each print passes
-	// 20 KB and a candidate page of them grows past what one sweep should hold.
+	// offsets and still overlap by minOverlapItems. Above 600s each print
+	// passes 20 KB and a candidate page of them grows past what one sweep
+	// should hold.
 	minChromaprintLengthSec = 30
 	maxChromaprintLengthSec = 600
 	// Unrelated audio sits near 0.5; a ceiling of 0.35 keeps a loosened
@@ -55,9 +56,9 @@ type FingerprintSettings struct {
 	AcousticMaxBitErrorRate float64
 	BackfillConcurrency     int32
 	SweepIntervalHours      int32
-	// AutoResolve lets the duplicate resolver (M498) act on its own: merge
-	// copies no release needs. Off, it only classifies, and every group waits
-	// for the operator.
+	// AutoResolve lets the duplicate resolver act on its own: merge copies no
+	// release needs. Off, it only classifies, and every group waits for an
+	// admin.
 	AutoResolve bool
 	// UpdatedAt is when the settings were last saved. Set by the database;
 	// ignored by Set.
@@ -143,7 +144,8 @@ func validateFingerprintSettings(in FingerprintSettings) error {
 	case in.ChromaprintLengthSec < minChromaprintLengthSec || in.ChromaprintLengthSec > maxChromaprintLengthSec:
 		return fmt.Errorf("%w: chromaprint_length_sec must be %d-%d",
 			ErrFingerprintSettingOutOfRange, minChromaprintLengthSec, maxChromaprintLengthSec)
-	// Written as a negated range so NaN, which fails every comparison, is refused.
+	// Written as a negated range so NaN, which fails every comparison, is
+	// refused.
 	case !(in.AcousticMaxBitErrorRate >= minAcousticMaxBitErrorRate && in.AcousticMaxBitErrorRate <= maxAcousticMaxBitErrorRate):
 		return fmt.Errorf("%w: acoustic_max_bit_error_rate must be %.2f-%.2f",
 			ErrFingerprintSettingOutOfRange, minAcousticMaxBitErrorRate, maxAcousticMaxBitErrorRate)