Relicense to MIT (v2.7.13)

The project's only runtime dependency is PyUSB (BSD-3-Clause) and it bundles
no third-party code (the PWA's DES/3DES is written from the FIPS 46-3 tables,
AES uses WebCrypto, the decoders come from the ISO 7816/ETSI/3GPP specs), so
nothing forced GPL; the GPL-2.0-or-later declaration is replaced with MIT.

- LICENSE: the MIT text, Copyright (c) 2026 Anton Troshin.
- pyproject: license = "MIT" + license-files = ["LICENSE"] (PEP 639), and the
  build requirement moves to setuptools>=77 for the SPDX form.  The wheel now
  carries dist-info/licenses/LICENSE and License-Expression: MIT, the sdist
  and the runtime zip carry LICENSE at the top.
- READMEs (EN/RU): a License section (original decoders/DES implementation,
  PyUSB as the only runtime dependency).
- tests: the packaging test pins the MIT declaration and the LICENSE text;
  the release-zip test requires LICENSE in the archive.
- version 2.7.13; SW cache v95.

Copies published before this tag (v2.7.10-v2.7.12) remain under the license
they were released with.

LICENSE

@@ -0,0 +1,21 @@
+MIT License
+
+Copyright (c) 2026 Anton Troshin
+
+Permission is hereby granted, free of charge, to any person obtaining a copy
+of this software and associated documentation files (the "Software"), to deal
+in the Software without restriction, including without limitation the rights
+to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+copies of the Software, and to permit persons to whom the Software is
+furnished to do so, subject to the following conditions:
+
+The above copyright notice and this permission notice shall be included in all
+copies or substantial portions of the Software.
+
+THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
+SOFTWARE.