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/replace.go

@@ -15,13 +15,13 @@ import (
 	syncpkg "git.fabledsword.com/bvandeusen/minstrel/internal/sync"
 )
 
-// Replacing a track with a better copy (M502 #5524).
+// Replacing a track with a better copy.
 //
 // An upgrade files the better copy first, as a track of its own, and only
 // then replaces the old one: its file is removed, then its likes, plays,
 // playlist entries and tags move onto the new row and the old row goes. It
 // is the duplicate merge with the survivor chosen by the import, and it
-// keeps the merge's order (#3918): if the old file cannot be removed nothing
+// keeps the merge's order: if the old file cannot be removed nothing
 // in the database changes, and the next scan finds the two copies as a
 // duplicate pair.