feat: set status to completed on anime completion

Check existing watchlist status — if already completed, just clear
progress and remove from continue watching. Otherwise upsert with
status 'completed'.

internal/domain/playback.go

@@ -35,6 +35,7 @@ type PlaybackRepository interface {
 	GetWatchListEntry(ctx context.Context, params db.GetWatchListEntryParams) (db.WatchListEntry, error)
 	GetContinueWatchingEntry(ctx context.Context, params db.GetContinueWatchingEntryParams) (db.ContinueWatchingEntry, error)
 	SaveWatchProgress(ctx context.Context, params db.SaveWatchProgressParams) error
+	UpsertWatchListEntry(ctx context.Context, params db.UpsertWatchListEntryParams) (db.WatchListEntry, error)
 	UpsertContinueWatchingEntry(ctx context.Context, params db.UpsertContinueWatchingEntryParams) (db.ContinueWatchingEntry, error)
 	DeleteContinueWatchingEntry(ctx context.Context, params db.DeleteContinueWatchingEntryParams) error
 }

internal/playback/repository/repository.go

@@ -26,6 +26,10 @@ func (r *playbackRepository) SaveWatchProgress(ctx context.Context, params db.Sa
 	return r.queries.SaveWatchProgress(ctx, params)
 }
 
+func (r *playbackRepository) UpsertWatchListEntry(ctx context.Context, params db.UpsertWatchListEntryParams) (db.WatchListEntry, error) {
+	return r.queries.UpsertWatchListEntry(ctx, params)
+}
+
 func (r *playbackRepository) UpsertContinueWatchingEntry(ctx context.Context, params db.UpsertContinueWatchingEntryParams) (db.ContinueWatchingEntry, error) {
 	return r.queries.UpsertContinueWatchingEntry(ctx, params)
 }

internal/playback/service/service.go

@@ -323,6 +323,24 @@ func (s *playbackService) BuildWatchData(ctx context.Context, animeID int, title
 }
 
 func (s *playbackService) CompleteAnime(ctx context.Context, userID string, animeID int64) error {
+	entry, err := s.repo.GetWatchListEntry(ctx, db.GetWatchListEntryParams{
+		UserID:  userID,
+		AnimeID: animeID,
+	})
+	if err != nil || entry.Status != "completed" {
+		_, err = s.repo.UpsertWatchListEntry(ctx, db.UpsertWatchListEntryParams{
+			ID:                 uuid.New().String(),
+			UserID:             userID,
+			AnimeID:            animeID,
+			Status:             "completed",
+			CurrentEpisode:     sql.NullInt64{Valid: false},
+			CurrentTimeSeconds: 0,
+		})
+		if err != nil {
+			return err
+		}
+	}
+
 	_ = s.repo.DeleteContinueWatchingEntry(ctx, db.DeleteContinueWatchingEntryParams{
 		UserID:  userID,
 		AnimeID: animeID,