feat: add helper functions for identifier and keyword validation

- Introduced `index.js` and `index.js.map` to export functions for checking identifier characters and names.
- Added `keyword.js` and `keyword.js.map` to implement functions for validating keywords and reserved words in JavaScript.
- Implemented various checks for strict and non-strict reserved words, including binding-specific checks.

backend/node_modules/@babel/helper-validator-identifier/lib/index.js

@@ -0,0 +1,57 @@
+"use strict";
+
+Object.defineProperty(exports, "__esModule", {
+  value: true
+});
+Object.defineProperty(exports, "isIdentifierChar", {
+  enumerable: true,
+  get: function () {
+    return _identifier.isIdentifierChar;
+  }
+});
+Object.defineProperty(exports, "isIdentifierName", {
+  enumerable: true,
+  get: function () {
+    return _identifier.isIdentifierName;
+  }
+});
+Object.defineProperty(exports, "isIdentifierStart", {
+  enumerable: true,
+  get: function () {
+    return _identifier.isIdentifierStart;
+  }
+});
+Object.defineProperty(exports, "isKeyword", {
+  enumerable: true,
+  get: function () {
+    return _keyword.isKeyword;
+  }
+});
+Object.defineProperty(exports, "isReservedWord", {
+  enumerable: true,
+  get: function () {
+    return _keyword.isReservedWord;
+  }
+});
+Object.defineProperty(exports, "isStrictBindOnlyReservedWord", {
+  enumerable: true,
+  get: function () {
+    return _keyword.isStrictBindOnlyReservedWord;
+  }
+});
+Object.defineProperty(exports, "isStrictBindReservedWord", {
+  enumerable: true,
+  get: function () {
+    return _keyword.isStrictBindReservedWord;
+  }
+});
+Object.defineProperty(exports, "isStrictReservedWord", {
+  enumerable: true,
+  get: function () {
+    return _keyword.isStrictReservedWord;
+  }
+});
+var _identifier = require("./identifier.js");
+var _keyword = require("./keyword.js");
+
+//# sourceMappingURL=index.js.map