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/source_markers.go

@@ -8,7 +8,7 @@ import (
 
 // sourceMarker is one sign that a file was ripped from a video rather than
 // taken from a release: words a video title carries and an album track does
-// not (#5410).
+// not.
 //
 // Each pattern is used twice, so it is written in the subset that Postgres's
 // regex flavour and Go's RE2 read the same way: no \b (Postgres spells word
@@ -21,9 +21,9 @@ type sourceMarker struct {
 	pattern string
 }
 
-// suspectSourceMarkers was calibrated against the operator's library on
-// 2026-10-08. Two candidates were left out on purpose:
-//   - "live in"/"live at": 229 files, nearly all from real live albums.
+// suspectSourceMarkers was calibrated against a real library. Two candidates
+// were left out on purpose:
+//   - "live in"/"live at": nearly all from real live albums.
 //   - a bare "reaction": it caught Beck's "Chain Reaction". The marker below
 //     wants the phrases a reaction video actually uses.
 var suspectSourceMarkers = []sourceMarker{