fix(tests): read documentation as UTF-8

Avoid Windows encoding failures when checking release documentation.

tests/test_release_shape.py

@@ -23,7 +23,7 @@ class ReleaseShapeTests(unittest.TestCase):
         self.assertEqual(len(samples), 3)
 
     def test_github_docs_copy_and_connection_guidance(self):
-        docs = (ROOT / "DOCS.md").read_text()
+        docs = (ROOT / "DOCS.md").read_text(encoding="utf-8")
         self.assertIn("official RexiMemo DNS service", docs)
         self.assertIn("Proxy Server", docs)
         self.assertIn("port to `8080`", docs)