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/eventbus.go

@@ -8,7 +8,7 @@ import (
 	"git.fabledsword.com/bvandeusen/minstrel/internal/eventbus"
 )
 
-// Package-level bus pointer for scan lifecycle events (#392). Set once
+// Package-level bus pointer for scan lifecycle events. Set once
 // at startup via SetEventBus; reads are nil-safe so test contexts that
 // never call SetEventBus simply skip publishing.
 //