fix: ensure root SPDX identifier and correct npm license metadata

LICENSE.md

@@ -1,3 +1,11 @@
+ip2region is dual-licensed under the Apache License 2.0 and the MIT License.
+
+You may use, distribute, and modify this software under either license,
+at your option. The full text of both licenses appears below.
+
+SPDX-License-Identifier: Apache-2.0 OR MIT
+
+==============================================================================
                                  Apache License
                            Version 2.0, January 2004
                         http://www.apache.org/licenses/

binding/javascript/package.json

@@ -31,11 +31,20 @@
     "ipv6-search"
   ],
   "author": "lionsoul2014",
-  "license": "ISC",
+  "license": "Apache-2.0 OR MIT",
   "bugs": {
     "url": "https://github.com/lionsoul2014/ip2region/issues"
   },
   "homepage": "https://github.com/lionsoul2014/ip2region#readme",
+  "files": [
+    "index.js",
+    "index.d.ts",
+    "searcher.js",
+    "util.js",
+    "README.md",
+    "README_zh.md",
+    "LICENSE.md"
+  ],
   "devDependencies": {
     "@types/jest": "^30.0.0",
     "argparse": "^2.0.1",