Change license to GPLv3 and add license headers to all files

package.json

@@ -1,4 +1,16 @@
 {
+  "//1": "This file is part of <project name>.",
+  "//2": "Copyright (C) 2024 Oscloud",
+  "//3": "This program is free software: you can redistribute it and/or modify",
+  "//4": "it under the terms of the GNU General Public License as published by",
+  "//5": "the Free Software Foundation, either version 3 of the License, or",
+  "//6": "(at your option) any later version.",
+  "//7": "This program is distributed in the hope that it will be useful,",
+  "//8": "but WITHOUT ANY WARRANTY; without even the implied warranty of",
+  "//9": "MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the",
+  "//10": "GNU General Public License for more details.",
+  "//11": "You should have received a copy of the GNU General Public License",
+  "//12": "along with this program. If not, see <https://www.gnu.org/licenses/>.",
   "lint-staged": {
     "**/*": "prettier --write --ignore-unknown"
   },
@@ -15,3 +27,4 @@
     "prepare": "husky install"
   }
 }
+