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/buildinfo/buildinfo.go

@@ -14,20 +14,18 @@ import "time"
 // release.yml passes it through the MINSTREL_VERSION build-arg → Dockerfile
 // ldflag.
 //
-// This carried the literal strings "main" and "dev" until 2026-09-10, which
-// made every image on a channel report the same thing forever. It stopped
-// being cosmetic when :vYYYY.MM.DD.HHMM image tags were retired (family rule
-// 145): this is now the ONLY thing that says which build is running.
+// Image tags carry no version, so this is the only thing that says which
+// build is running.
 var Version = "dev"
 
 // Channel is which line this build came off — "stable" or "dev", or "local"
 // for a plain `docker build`.
 //
-// A SIBLING FIELD, never a suffix inside Version (family rule 149). The same
+// A sibling field, never a suffix inside Version. The same
 // commit built on both lanes reports the same version and differs only here;
 // folding the two together is what makes a version string stop being
 // comparable.
 var Channel = "local"
 
-// Started is when this process started, for the Overview's uptime (M504).
+// Started is when this process started, for the admin Overview's uptime.
 var Started = time.Now()