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/server/server.go

@@ -65,34 +65,34 @@ type Server struct {
 	// When nil, Router() constructs a local fallback (test contexts).
 	Bus *eventbus.Bus
 	// PlaylistScheduler fires per-user daily system-playlist builds at
-	// 03:00 in each user's stored timezone (#392 Half B). Constructed
+	// 03:00 in each user's stored timezone. Constructed
 	// in cmd/minstrel/main.go and threaded into the API handlers so
 	// PUT /api/me/timezone and POST /api/auth/register can call
 	// Refresh synchronously.
 	PlaylistScheduler *playlists.Scheduler
-	// RecSettings is the DB-backed recommendation tuning lab (#1250):
+	// RecSettings is the DB-backed recommendation tuning:
 	// scoring-weight profiles + taste-build knobs. Constructed in
 	// cmd/minstrel/main.go (it pushes daily-mix weights into package
 	// playlists at boot); the API layer reads radio weights per request
 	// and serves the admin tuning endpoints from it. Router() constructs
 	// a fallback when nil (tests).
 	RecSettings *recsettings.Service
-	// FingerprintSettings is the DB-backed fingerprinting policy (M400 #3913).
+	// FingerprintSettings is the DB-backed fingerprinting policy.
 	// Constructed in cmd/minstrel/main.go and shared with the scanner and the
 	// fingerprint workers, so a save from the admin card reaches them without a
 	// restart. Router() constructs a fallback when nil (tests).
 	FingerprintSettings *library.FingerprintSettingsService
-	// LoudnessSettings is the DB-backed loudness analysis policy (M464 #4995),
+	// LoudnessSettings is the DB-backed loudness analysis policy,
 	// shared with the loudness backfill. Nil makes the router load its own.
 	LoudnessSettings *library.LoudnessSettingsService
-	// AcoustIDLookup is the AcoustID lookup worker (M401), whose settings,
+	// AcoustIDLookup is the AcoustID lookup worker, whose settings,
 	// status and "look up now" the admin card drives. Nil in test contexts;
 	// one is built (and never run) so the admin routes still answer.
 	AcoustIDLookup *library.AcoustIDLookupWorker
-	// ReacqSettings is the DB-backed missing-file re-acquisition policy
-	// (milestone #290) — the same instance the sweeper in cmd/minstrel/main.go
-	// reads, so a save from the admin card reaches it without a restart
-	// (#3936). Router() constructs a fallback when nil (tests).
+	// ReacqSettings is the DB-backed missing-file re-acquisition policy — the
+	// same instance the sweeper in cmd/minstrel/main.go reads, so a save from
+	// the admin card reaches it without a restart. Router() constructs a
+	// fallback when nil (tests).
 	ReacqSettings *reacquisition.SettingsService
 	// StreamSecret is the HMAC key used by /api/cast/stream-token to
 	// mint signed UPnP / Sonos stream URLs and by /api/tracks/{id}/stream
@@ -154,13 +154,11 @@ func (s *Server) Router() http.Handler {
 		tracksSvc := tracks.NewService(s.Pool, s.Logger, s.DataDir)
 		playlistsSvc := playlists.NewService(s.Pool, s.Logger, s.DataDir)
 		smtpSender := mailer.NewSMTPSender(s.Pool, s.Logger.With("component", "mailer"))
-		// Live-event bus for SSE subscribers (#392). Constructed per-process;
-		// producers in playevents / requests / scanner publish into
-		// the same instance. Background workers (request reconciler, scan
-		// scheduler) live in cmd/minstrel/main.go where they're constructed
-		// before Router() runs; they read s.Bus directly so they share this
-		// process's bus. When Router() runs before main set the bus (tests,
-		// or future contexts) we fall back to a fresh local instance.
+		// Live-event bus for SSE subscribers, one per process: producers in
+		// playevents / requests / scanner publish into the same instance.
+		// Background workers are built in cmd/minstrel/main.go before Router()
+		// runs and share s.Bus. With no bus set (tests), a fresh local one is
+		// used.
 		bus := s.Bus
 		if bus == nil {
 			bus = eventbus.New()
@@ -240,8 +238,8 @@ func (s *Server) handleHealthz(w http.ResponseWriter, _ *http.Request) {
 }
 
 // handleAdminScan runs a scan synchronously and returns the resulting stats.
-// Kept synchronous for v1: libraries are small and the operator can tell when
-// it's done. Async jobs with status polling are a later-milestone concern.
+// Synchronous, so the caller can tell when it's done; the scan's progress is
+// also published as scan-run events.
 func (s *Server) handleAdminScan(w http.ResponseWriter, r *http.Request) {
 	stats, err := s.Scanner.Scan(r.Context(), nil)
 	w.Header().Set("Content-Type", "application/json")