fix: Fix vector with KATO geometry

internal/repository/postgres/dataset.go

@@ -166,11 +166,22 @@ func (r *DatasetRepository) SetProperties(ctx context.Context, id uuid.UUID, pro
 	return nil
 }
 
-// MarkReady sets the dataset status to ready and clears any error.
-func (r *DatasetRepository) MarkReady(ctx context.Context, id uuid.UUID) error {
+// MarkReady sets the dataset status to ready, stores the dissolved feature
+// geometry (GeoJSON in EPSG:4326; nil keeps the existing geometry, reduced to
+// the union of all features via ST_UnaryUnion), and clears any error.
+func (r *DatasetRepository) MarkReady(ctx context.Context, id uuid.UUID, geometry []byte) error {
+	var geom any // nil -> SQL NULL -> CASE keeps existing geometry
+	if len(geometry) > 0 {
+		geom = string(geometry)
+	}
 	tag, err := r.pool.Exec(ctx,
-		`UPDATE datasets SET status = $2, parse_error = NULL, updated_at = now() WHERE id = $1`,
-		id, domain.DatasetStatusReady,
+		`UPDATE datasets
+		 SET status = $2,
+		     geometry = CASE WHEN $3::text IS NULL THEN geometry
+		                     ELSE ST_UnaryUnion(ST_SetSRID(ST_GeomFromGeoJSON($3), 4326)) END,
+		     parse_error = NULL, updated_at = now()
+		 WHERE id = $1`,
+		id, domain.DatasetStatusReady, geom,
 	)
 	if err != nil {
 		return mapError(err)