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/subsonic/types.go

@@ -181,7 +181,7 @@ type SongRef struct {
 	BitRate     int      `json:"bitRate,omitempty" xml:"bitRate,attr,omitempty"`
 	IsDir       bool     `json:"isDir" xml:"isDir,attr"`
 	Type        string   `json:"type" xml:"type,attr"`
-	// ReplayGain is OpenSubsonic's replayGain (M464 #4997): Minstrel's own
+	// ReplayGain is OpenSubsonic's replayGain: Minstrel's own
 	// measurements, so third-party clients that level by ReplayGain do it
 	// from the same numbers the Minstrel apps use. Omitted until measured.
 	ReplayGain *ReplayGain `json:"replayGain,omitempty" xml:"replayGain,omitempty"`