Release package version 1.0.0

Added first files

package.json

@@ -1,5 +1,5 @@
 {
-  "name": "template-of-lib-repo",
+  "name": "gxc-lett-js",
   "version": "0.0.0",
   "main": "index.js",
   "scripts": {
@@ -12,12 +12,14 @@
     "prettier:fix": "prettier --write \"./lib/src/**/*.*\"",
     "lint": "eslint lib/src/**/*.ts",
     "prepare": "husky",
-    "test": "echo test"
+    "test": "jest ./lib/src",
+    "test:watch": "jest ./lib/src --watch"
   },
   "author": "",
   "license": "ISC",
   "description": "",
   "devDependencies": {
+    "@types/jest": "^29.5.12",
     "@eslint/eslintrc": "^3.3.4",
     "@eslint/js": "^10.0.1",
     "@types/node": "^25.3.3",
@@ -25,8 +27,10 @@
     "eslint": "^10.0.2",
     "globals": "^17.4.0",
     "husky": "^9.1.7",
+    "jest": "^29.7.0",
     "prettier": "^3.8.1",
     "rimraf": "^6.0.1",
+    "ts-jest": "^29.2.4",
     "typescript": "^5.9.3",
     "vite": "^7.3.1"
   }