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/catalogue/art.go

@@ -17,7 +17,7 @@ import (
 // the sources are asked again.
 const NoArtRetry = 7 * 24 * time.Hour
 
-// fetchTimeout bounds one look-up across every source (rule 156).
+// fetchTimeout bounds one look-up across every source.
 const fetchTimeout = 30 * time.Second
 
 // ErrNoArt: no enabled source has an image, or the sources could not be
@@ -32,7 +32,7 @@ func ValidMBID(s string) bool { return mbidPattern.MatchString(s) }
 
 // Art serves images for artists and release groups that are not in the
 // library (search results, Discover suggestions, wanted albums), from the
-// operator's enabled cover-art sources. Each image is fetched once and kept
+// enabled cover-art sources. Each image is fetched once and kept
 // under the data directory, so the browser only ever talks to Minstrel.
 type Art struct {
 	dir           string
@@ -51,7 +51,7 @@ type artCall struct {
 }
 
 // ArtSources lists the image sources to ask, in order. The cover-art
-// settings service is one: it answers with what the operator has enabled.
+// settings service is one: it answers with the sources an admin enabled.
 type ArtSources interface {
 	EnabledArtistProviders() []coverart.ArtistArtProvider
 	EnabledAlbumProviders() []coverart.AlbumCoverProvider