feat(notifications): requests and flags reach the people who act on them (#5340)

- A new request still pending after any auto-approval notifies the
  admins (request_pending), but not the requester if they are an admin.
  A request that dedups into one already in flight is not announced again.
- Approving or rejecting a request notifies the requester, and a
  rejection carries the admin's notes as the reason. An admin deciding
  their own request gets nothing.
- The reconciler notifies the requester when their request arrives
  (request_completed), linking the matched album or artist.
- A request the re-acquisition sweeper files and cannot approve itself
  notifies the admins.
- A quarantine flag notifies every admin except the flagger, naming the
  track, the flagger and the reason.

lidarrrequests.Service.CreateTracked reports whether a request was
inserted or deduped; Create wraps it.

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

internal/lidarrrequests/service.go

@@ -80,8 +80,16 @@ func NewService(pool *pgxpool.Pool, cfg *lidarrconfig.Service, clientFn func() *
 // Create validates the kind→required-fields invariant and inserts a
 // pending row.
 func (s *Service) Create(ctx context.Context, userID pgtype.UUID, p CreateParams) (dbq.LidarrRequest, error) {
+	row, _, err := s.CreateTracked(ctx, userID, p)
+	return row, err
+}
+
+// CreateTracked is Create, also reporting whether a row was inserted. A
+// request that dedupes into one already in flight is not new, so callers
+// that announce new requests (M489) say nothing for it.
+func (s *Service) CreateTracked(ctx context.Context, userID pgtype.UUID, p CreateParams) (dbq.LidarrRequest, bool, error) {
 	if err := validateKindFields(p); err != nil {
-		return dbq.LidarrRequest{}, err
+		return dbq.LidarrRequest{}, false, err
 	}
 	q := dbq.New(s.pool)
 	// Dedup: if a non-terminal request for this MBID already exists,
@@ -97,9 +105,9 @@ func (s *Service) Create(ctx context.Context, userID pgtype.UUID, p CreateParams
 		dedupMBID = p.LidarrTrackMBID
 	}
 	if existing, derr := q.GetNonTerminalRequestForMBID(ctx, dedupMBID); derr == nil {
-		return existing, nil
+		return existing, false, nil
 	} else if !errors.Is(derr, pgx.ErrNoRows) {
-		return dbq.LidarrRequest{}, fmt.Errorf("create: dedup check: %w", derr)
+		return dbq.LidarrRequest{}, false, fmt.Errorf("create: dedup check: %w", derr)
 	}
 	row, err := q.CreateLidarrRequest(ctx, dbq.CreateLidarrRequestParams{
 		UserID:           userID,
@@ -112,9 +120,25 @@ func (s *Service) Create(ctx context.Context, userID pgtype.UUID, p CreateParams
 		TrackTitle:       strPtr(p.TrackTitle),
 	})
 	if err != nil {
-		return dbq.LidarrRequest{}, fmt.Errorf("create: %w", err)
+		return dbq.LidarrRequest{}, false, fmt.Errorf("create: %w", err)
 	}
-	return row, nil
+	return row, true, nil
+}
+
+// DisplayName is a request as a person would say it: "Moe Shop" for an
+// artist, "Moe Shop – WWW" for an album or a track.
+func DisplayName(row dbq.LidarrRequest) string {
+	switch row.Kind {
+	case dbq.LidarrRequestKindTrack:
+		if row.TrackTitle != nil && *row.TrackTitle != "" {
+			return row.ArtistName + " – " + *row.TrackTitle
+		}
+	case dbq.LidarrRequestKindAlbum:
+		if row.AlbumTitle != nil && *row.AlbumTitle != "" {
+			return row.ArtistName + " – " + *row.AlbumTitle
+		}
+	}
+	return row.ArtistName
 }
 
 func validateKindFields(p CreateParams) error {