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_settings.go

@@ -12,13 +12,13 @@ import (
 	"git.fabledsword.com/bvandeusen/minstrel/internal/db/dbq"
 )
 
-// AcoustID lookup settings (M401 #3922). Rule 25: a database row, changed
-// without a restart, shared by the worker and the admin API.
+// AcoustID lookup settings: a database row, changed without a restart, shared
+// by the worker and the admin API.
 
 // AcoustIDSettings mirrors the acoustid_settings row.
 type AcoustIDSettings struct {
 	Enabled bool
-	// APIKey is the operator's registered application key. Never sent back
+	// APIKey is the registered AcoustID application key. Never sent back
 	// to the browser; the API reports only whether one is set.
 	APIKey string
 	// MinScore is the AcoustID score a recording needs to be considered.