docs: server comments say what the code does, not how it came to be (#6277)

Comment blocks in cmd/minstrel and 30 smaller internal packages, rewritten
to rule 32's standard with each citation read in context: task, milestone
and rule ids go, and so do the stories they were attached to ("used to",
"Before #N", measurements from one install, quotes, pointers to Fabled
Librarian's records and to docs/superpowers files that are not in the
repo). Where a story wrapped a real constraint, the constraint stays as a
present-tense fact.

Comments that had gone stale are corrected:
- taste.Config: the tuned values are overlaid by internal/recsettings;
  it is no longer "a later follow-up".
- StorageConfig: the data dir holds art, caches and the stream secret,
  not only playlist covers.
- the Subsonic album list and getUser comments describe what they do
  today rather than a milestone that would change it.

Checked: the non-comment token stream of every changed file matches
HEAD, and gofmt -l is empty.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

internal/similarity/worker.go

@@ -5,14 +5,14 @@
 //
 // For recordings it keeps LB's whole answer in listenbrainz_similar_recordings
 // and derives the track_similarity edges from it in SQL, against whatever is
-// in the library at the time (#5296). Matching once at fetch time missed every
-// recording that reached the library afterwards, through an import or an MBID
-// the AcoustID lookup filled in. For artists it stores the in-library matches in
-// artist_similarity and the rest in artist_similarity_unmatched, as before.
+// in the library at the time, so a recording that reaches the library later
+// (an import, or an MBID the AcoustID lookup fills in) gains its edges without
+// asking LB again. For artists it stores the in-library matches in
+// artist_similarity and the rest in artist_similarity_unmatched.
 //
 // Every answer is recorded as a fetch, an empty one included, and the queue
-// reads those records: freshness used to be read from the edges, so a seed
-// that matched nothing was never fresh and held the head of the queue.
+// reads those records rather than the edges: a seed that matched nothing is
+// still fresh and does not hold the head of the queue.
 package similarity
 
 import (
@@ -200,8 +200,8 @@ func (w *Worker) upsertArtistSimilar(ctx context.Context, q *dbq.Queries, artist
 	}
 	sort.Slice(results, func(i, j int) bool { return results[i].Score > results[j].Score })
 	// Scores are stored relative to the seed's closest artist, as track edges
-	// are (#6177): LB's raw scores are counts (16 to 10,875 on the operator's
-	// library), and both the candidate pool and the suggestions read 0 to 1.
+	// are: LB's raw scores are unbounded counts, and both the candidate pool
+	// and the suggestions read 0 to 1.
 	best := results[0].Score
 
 	mbids := make([]string, 0, len(results))