chore: GPL-3.0 license propagated into *.go files in backend

backend/cmd/main.go

@@ -1,7 +1,24 @@
+// Copyright (c) 2025 Nikolai Papin
+// 
+// This file is part of Easywish
+// 
+// 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/>.
+
 // @title           Easywish client API
 // @version         1.0
 // @description     Easy and feature-rich wishlist.
-// @license.name  	GPL 3.0
+// @license.name  	GPL-3.0
 
 // @BasePath  			/api/
 // @Schemes					http
@@ -90,4 +107,3 @@ func main() {
 
   ).Run()
 }
-