add missing copyright headers

Author: elliotcubit

src/args.rs

@@ -1,3 +1,20 @@
+// Copyright 2025 Elaine Cubit
+//
+// This file is part of polybar-mpris-watcher-rs.
+//
+// polybar-mpris-watcher-rs 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.
+//
+// polybar-mpris-watcher-rs 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/>. 
+
 use clap::{
     ValueEnum,
     Parser,

src/control.rs

@@ -1,3 +1,20 @@
+// Copyright 2025 Elaine Cubit
+//
+// This file is part of polybar-mpris-watcher-rs.
+//
+// polybar-mpris-watcher-rs 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.
+//
+// polybar-mpris-watcher-rs 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/>. 
+
 use crate::args::Operation;
 use mpris::{
     PlayerFinder