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.

tests/test_packaging.py

@@ -70,6 +70,15 @@ class TestDistributionMetadata(unittest.TestCase):
         # The sdist carries frontend/, so a wheel built from it has the PWA.
         self.assertIn('graft frontend', self._read('MANIFEST.in'))
 
+    def test_license_is_mit(self):
+        # The project is MIT; the metadata and the file must not drift apart.
+        pyproject = self._read('pyproject.toml')
+        self.assertIn('license = "MIT"', pyproject)
+        self.assertIn('license-files = ["LICENSE"]', pyproject)
+        license_text = self._read('LICENSE')
+        self.assertTrue(license_text.startswith('MIT License\n'))
+        self.assertIn('Permission is hereby granted, free of charge', license_text)
+
     def test_setup_py_bundles_the_pwa(self):
         setup_py = self._read('setup.py')
         self.assertIn('frontend', setup_py)

tests/test_pcap_import.py

@@ -224,7 +224,7 @@ class TestImportEndpoint(unittest.TestCase):
 class TestVersion(unittest.TestCase):
     def test_package_version(self):
         from simtrace2_pysniff import __version__
-        self.assertEqual(__version__, '2.7.12')
+        self.assertEqual(__version__, '2.7.13')
 
     def test_status_includes_version(self):
         import os

tests/test_release_zip.py

@@ -51,6 +51,7 @@ class TestReleaseZip(unittest.TestCase):
                 'sniff-start.sh',
                 'sniff-start.bat',
                 '70-simtrace2-pysniff.rules',
+                'LICENSE',
                 'README.md'):
             self.assertIn('%s/%s' % (top, rel), self.names)