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/notifications/render_test.go

@@ -45,7 +45,7 @@ func TestRender_CoalescedCountsReadNaturally(t *testing.T) {
 	require.Equal(t, "Some tracks went missing", Render(KindTracksMissing, []byte(`{}`)).Title)
 }
 
-// M542: a notice says which, not only how many.
+// A notice says which, not only how many.
 func TestRender_NamesWhatChanged(t *testing.T) {
 	require.Equal(t, "No longer on disk: Weezer – Buddy Holly.",
 		render(KindTracksMissing, Payload{Count: 1, Items: []string{"Weezer – Buddy Holly"}}).Body)