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/coplay/worker.go

@@ -1,11 +1,10 @@
-// Package coplay builds household co-play similarity edges (#1533, milestone
-// #160 Opt 5). Minstrel is a single shared-library, multi-user server (no
-// per-user library ACL), so the "household" is the whole instance's user set.
-// A periodic worker recomputes artist–artist co-occurrence from play_events
-// entirely in SQL (no external API) and stores the edges in artist_similarity
-// under source='user_cooccurrence' — the pre-provisioned co-occurrence source
-// from the 0009 schema — which the radio/mix candidate pool consumes as a
-// collaborative arm. Single-user servers produce no edges (the >= 2 co-player
+// Package coplay builds household co-play similarity edges. Minstrel is a
+// single shared-library, multi-user server (no per-user library ACL), so the
+// "household" is the whole instance's user set. A periodic worker recomputes
+// artist–artist co-occurrence from play_events entirely in SQL (no external
+// API) and stores the edges in artist_similarity under
+// source='user_cooccurrence', which the radio/mix candidate pool consumes as
+// a collaborative arm. Single-user servers produce no edges (the >= 2 co-player
 // gate), so the feature is a graceful no-op there.
 package coplay