完善一键回归与真实输入准备

backend/internal/store/postgres/dev_store.go

@@ -23,6 +23,7 @@ type DemoBootstrapSummary struct {
 	VariantManualEventID string `json:"variantManualEventId"`
 	VariantManualRelease string `json:"variantManualReleaseId"`
 	VariantManualCardID  string `json:"variantManualCardId"`
+	CleanedSessionCount  int64  `json:"cleanedSessionCount"`
 }
 
 func (s *Store) EnsureDemoData(ctx context.Context) (*DemoBootstrapSummary, error) {
@@ -597,6 +598,23 @@ func (s *Store) EnsureDemoData(ctx context.Context) (*DemoBootstrapSummary, erro
 		return nil, fmt.Errorf("ensure variant manual demo card: %w", err)
 	}
 
+	var cleanedSessionCount int64
+	if err := tx.QueryRow(ctx, `
+		WITH cleaned AS (
+			UPDATE game_sessions
+			SET
+				status = 'cancelled',
+				ended_at = NOW(),
+				updated_at = NOW()
+			WHERE event_id = ANY($1::uuid[])
+			  AND status IN ('launched', 'running')
+			RETURNING 1
+		)
+		SELECT COUNT(*) FROM cleaned
+	`, []string{eventID, manualEventID}).Scan(&cleanedSessionCount); err != nil {
+		return nil, fmt.Errorf("cleanup demo ongoing sessions: %w", err)
+	}
+
 	if err := tx.Commit(ctx); err != nil {
 		return nil, err
 	}
@@ -619,5 +637,6 @@ func (s *Store) EnsureDemoData(ctx context.Context) (*DemoBootstrapSummary, erro
 		VariantManualEventID: "evt_demo_variant_manual_001",
 		VariantManualRelease: manualReleaseRow.PublicID,
 		VariantManualCardID:  manualCardPublicID,
+		CleanedSessionCount:  cleanedSessionCount,
 	}, nil
 }