feat: add license notices

pyproject.toml

@@ -1,8 +1,24 @@
+# Copyright (C) 2026 Asger Gitz-Johansen
+#
+# This program is free software: you can redistribute it and/or modify
+# it under the terms of the GNU General Public License as published by
+# the Free Software Foundation, either version 3 of the License, or
+# (at your option) any later version.
+#
+# This program 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 General Public License for more details.
+#
+# You should have received a copy of the GNU General Public License
+# along with this program.  If not, see <https://www.gnu.org/licenses/>.
+
 [project]
 name = "sleep-detection"
 version = "0.1.0"
 description = "Add your description here"
 readme = "README.md"
+license = "GPL-3.0-or-later"
 authors = [
     { name = "Asger Gitz-Johansen", email = "asger.gitz@hotmail.com" }
 ]