feat: a wanted list — follow artists on release-type profiles; requests and re-acquisition become wants (M502 #5520)

Minstrel keeps its own list of what it is to get, keyed by MusicBrainz
release group. A want comes from an approved request, a new release by a
followed artist, or an album whose files went missing, and is held once the
library has a full edition of it.

- Migration 0081: release_type_profiles (Standard seeded: Album, EP,
  Single, studio only), follows, follow_seen_groups and wants.
  lidarr_requests becomes requests with plain *_mbid columns; approved
  album and track requests move onto the wanted list, approved artist
  requests become follows, and the library's album artists start out
  followed. missing_reacquisitions and the retry settings go.
- internal/wanted: follows are checked against MusicBrainz discographies
  daily. The first check sets a baseline, and only releases after it are
  wanted unless the follow asked for what already exists. Profiles filter
  by primary and secondary type, so live recordings stay out unless a
  profile ticks Live.
- internal/requests (was lidarrrequests): approving puts the request on
  the wanted list, and an artist request can be approved on a chosen
  profile. A request completes when its want is held.
- The re-acquisition sweeper wants a missing album back instead of asking
  Lidarr; searching for it is the search schedule's (#5521).
- Web: an admin Wanted page (Wanted, Missing files, Held, Following), a
  follow control on artist pages, a release-type profiles card on
  Integrations, "Approve on a profile" on Requests, and want state on
  Missing files. The artist detail API returns the artist's MBID.
- Android: the request body sends artist_mbid, album_mbid and track_mbid.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

cmd/minstrel/main.go

@@ -23,15 +23,13 @@ import (
 	"git.fabledsword.com/bvandeusen/minstrel/internal/eventbus"
 	"git.fabledsword.com/bvandeusen/minstrel/internal/gc"
 	"git.fabledsword.com/bvandeusen/minstrel/internal/library"
-	"git.fabledsword.com/bvandeusen/minstrel/internal/lidarr"
-	"git.fabledsword.com/bvandeusen/minstrel/internal/lidarrconfig"
-	"git.fabledsword.com/bvandeusen/minstrel/internal/lidarrrequests"
 	"git.fabledsword.com/bvandeusen/minstrel/internal/logging"
 	"git.fabledsword.com/bvandeusen/minstrel/internal/mailer"
 	"git.fabledsword.com/bvandeusen/minstrel/internal/notifications"
 	"git.fabledsword.com/bvandeusen/minstrel/internal/playlists"
 	"git.fabledsword.com/bvandeusen/minstrel/internal/reacquisition"
 	"git.fabledsword.com/bvandeusen/minstrel/internal/recsettings"
+	"git.fabledsword.com/bvandeusen/minstrel/internal/requests"
 	"git.fabledsword.com/bvandeusen/minstrel/internal/scrobble"
 	"git.fabledsword.com/bvandeusen/minstrel/internal/scrobble/listenbrainz"
 	"git.fabledsword.com/bvandeusen/minstrel/internal/server"
@@ -39,6 +37,7 @@ import (
 	"git.fabledsword.com/bvandeusen/minstrel/internal/subsonic"
 	syncpkg "git.fabledsword.com/bvandeusen/minstrel/internal/sync"
 	"git.fabledsword.com/bvandeusen/minstrel/internal/tags"
+	"git.fabledsword.com/bvandeusen/minstrel/internal/wanted"
 )
 
 func main() {
@@ -292,10 +291,8 @@ func run() error {
 	gcWorker := gc.NewWorker(pool, logger.With("component", "gc"))
 	go gcWorker.Run(ctx)
 
-	// Start the Lidarr reconciler worker. Per spec §M5a, polls pending Lidarr
-	// import requests and reconciles them against the library. Short-circuits
-	// to no-op when lidarr_config.enabled = false.
-	lidarrCfg := lidarrconfig.New(pool)
+	// The request reconciler completes approved requests once the library
+	// holds what they asked for (M502 #5520: wants, not Lidarr adds).
 	// Live-event bus shared between SSE subscribers (api.Mount) and
 	// background workers that publish (reconciler today; scanner later).
 	// Constructed before any service that publishes so they all share the
@@ -305,31 +302,25 @@ func run() error {
 	// threading the bus through RunScan + TryStartScan + the Scheduler
 	// + every test caller. Per-process singleton, set once at startup.
 	library.SetEventBus(bus)
-	// Per-tick Lidarr client factory: re-reads config so an admin save
-	// takes effect without a restart, returning nil while Lidarr is
-	// disabled/unconfigured. Mirrors server.go's lidarrClientFn; the
-	// reconciler uses it to (re)send unconfirmed adds.
-	lidarrClientFn := func() *lidarr.Client {
-		c, cerr := lidarrCfg.Get(ctx)
-		if cerr != nil || !c.Enabled || c.BaseURL == "" || c.APIKey == "" {
-			return nil
-		}
-		return lidarr.NewClient(c.BaseURL, c.APIKey)
-	}
 	// The notifications inbox's one writer (M489), shared by every
 	// background producer started here. The API builds its own over the
 	// same pool and bus.
 	notifier := notifications.New(pool, bus, logger.With("component", "notifications"))
 
-	lidarrReconciler := lidarrrequests.NewReconciler(pool, lidarrCfg, lidarrClientFn, logger.With("component", "lidarr"), bus)
-	lidarrReconciler.SetNotifier(notifier)
+	requestReconciler := requests.NewReconciler(pool, logger.With("component", "requests"), bus)
+	requestReconciler.SetNotifier(notifier)
 	library.SetNotifier(notifier)
-	go lidarrReconciler.Run(ctx)
+	go requestReconciler.Run(ctx)
 
 	// Release catalogue (M502 #5519): re-reads discographies older than a
 	// week from MusicBrainz, a batch an hour, through the process-wide
 	// MusicBrainz pacer it shares with tag enrichment.
-	go catalogue.New(pool, nil, logger.With("component", "catalogue")).Run(ctx)
+	cat := catalogue.New(pool, nil, logger.With("component", "catalogue"))
+	go cat.Run(ctx)
+
+	// The wanted list (M502 #5520): reads followed artists' discographies
+	// daily for new releases and marks wants held once the library has them.
+	go wanted.New(pool, cat, logger.With("component", "wanted")).Run(ctx)
 
 	// Duplicate resolver (M498, M502): classifies the sweep's groups and, with
 	// the operator's auto-resolve on, merges the copies that are safe to merge.
@@ -338,11 +329,10 @@ func run() error {
 	go library.NewDuplicateResolveWorker(pool, logger.With("component", "duplicate_resolve"),
 		cfg.Storage.DataDir, fpSettings).Run(ctx)
 
-	// Missing-file re-acquisition (milestone #290). Turns albums whose files
-	// have been gone longer than the grace window into Lidarr requests, on an
-	// exponential per-album backoff. Hourly tick — the shortest meaningful
-	// backoff is measured in hours, so waking more often would only re-read
-	// settings and find nothing due.
+	// Missing-file re-acquisition (milestone #290, M502 #5520). Wants back
+	// albums whose files have been gone longer than the grace window; the
+	// search schedule looks for them. Hourly tick — the grace window is
+	// measured in hours.
 	//
 	// A settings-load failure is logged, not fatal: NewSettingsService always
 	// returns a usable service holding the defaults, and running on defaults
@@ -353,14 +343,7 @@ func run() error {
 	if reacqErr != nil {
 		logger.Warn("reacquisition: using default settings", "err", reacqErr)
 	}
-	reacqSweeper := reacquisition.NewSweeper(
-		pool,
-		reacqSettings,
-		lidarrrequests.NewService(pool, lidarrCfg, lidarrClientFn, nil),
-		logger.With("component", "reacquisition"),
-	)
-	reacqSweeper.SetNotifier(notifier)
-	go reacqSweeper.Run(ctx)
+	go reacquisition.NewSweeper(pool, reacqSettings, logger.With("component", "reacquisition")).Run(ctx)
 
 	// library_changes compactor (#357 follow-up). Daily tick; deletes
 	// rows older than the configured retention so the change-log table