A license more specific to source code should be used

[VonUniGE]

A license more specific to source code should be used.
See Can I apply a Creative Commons license to software?

[gagarine]

Especially CC BY-NC-SA 4.0 is not an open license notably because of the NC that block virtually all usage.

I would suggest AGPL3

[agilare]

Additionally to LICENSE file and "Licence" in README do you suggest to add license text in header of each source code file, like explained in https://www.gnu.org/licenses/gpl-howto.html ?
If yes, adding in each file something like

 * Copyright (C) 2007 - 2023 Michel Gaudry <[email protected]>
 *
 * This file is part of ladecadanse.
 * 
 * ladecadanse is free software: you can redistribute it and/or modify
 * it under the terms of the GNU Affero General Public License as published by
 * the Free Software Foundation, either version 3 of the License, or
 * any later version.
 *
 * ladecadanse is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU Affero General Public License for more details.
 *
 * You should have received a copy of the GNU Affero General Public License
 * along with ladecadanse.  If not, see <http://www.gnu.org/licenses/>.
*/

is is a bit cumbersome. I've seen lighter alternatives like

/* 
 * @package ladecadanse
 * @copyright  Copyright (c) 2007 - 2023 Michel Gaudry <[email protected]>
 * @license    AGPL License; see LICENSE file for details.
 */

or

/*
 * This file is part of ladecadanse
 *
 * (c) 2007 - 2023 Michel Gaudry <[email protected]>
 *
 * For the full copyright and license information, please view the LICENSE
 * file that was distributed with this source code.
 */

that might be suitable

[agilare]

Completed with cd1dd54 and continues in #70