fix: Fix geometry parsing

internal/repository/postgres/dataset.go

@@ -139,12 +139,23 @@ func (r *DatasetRepository) MarkConverted(ctx context.Context, id uuid.UUID, cog
 	return nil
 }
 
-// SetProperties stores the extracted attribute table (nil -> NULL) and marks the
-// dataset ready.
-func (r *DatasetRepository) SetProperties(ctx context.Context, id uuid.UUID, properties []byte) error {
+// SetProperties stores the extracted attribute table (nil -> NULL) and the
+// dissolved feature geometry (GeoJSON in EPSG:4326; nil keeps the existing
+// geometry), then marks the dataset ready. The geometry is reduced to the union
+// of all features via ST_UnaryUnion.
+func (r *DatasetRepository) SetProperties(ctx context.Context, id uuid.UUID, properties, 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 properties = $2, status = $3, parse_error = NULL, updated_at = now() WHERE id = $1`,
-		id, nullableJSON(json.RawMessage(properties)), domain.DatasetStatusReady,
+		`UPDATE datasets
+		 SET properties = $2,
+		     geometry = CASE WHEN $3::text IS NULL THEN geometry
+		                     ELSE ST_UnaryUnion(ST_SetSRID(ST_GeomFromGeoJSON($3), 4326)) END,
+		     status = $4, parse_error = NULL, updated_at = now()
+		 WHERE id = $1`,
+		id, nullableJSON(json.RawMessage(properties)), geom, domain.DatasetStatusReady,
 	)
 	if err != nil {
 		return mapError(err)