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/library_paths.go

@@ -15,7 +15,7 @@ import (
 	"git.fabledsword.com/bvandeusen/minstrel/internal/db/dbq"
 )
 
-// The library's folders (#6129). They are set in Settings and changed without
+// The library's folders. They are set in Settings and changed without
 // a restart; MINSTREL_LIBRARY_SCAN_PATHS names them until the first save. The
 // Scanner holds the live list, and the watcher and the importer read it there.
 //
@@ -51,7 +51,7 @@ type RerootResult struct {
 }
 
 // RootsError is a save the folders refuse. Its text says why, in a sentence
-// for the operator.
+// for an admin.
 type RootsError struct{ msg string }
 
 func (e *RootsError) Error() string { return e.msg }