Add the LICENSE file that package.json already declares

Hi — thanks for building opencode-cursor.

`package.json` declares `"license": "MIT"`, but the repository contains no
LICENSE file, so GitHub reports the project as unlicensed and downstream
users have no full MIT text (with your copyright line) to rely on and
reproduce.

Would you add a standard MIT `LICENSE` file (e.g. `Copyright (c) 2026
Ephraim Duncan`) matching the package.json declaration?

Context: I'm building ganja, a Rust behavioral port of opencode
(https://github.com/zchee/ganja-code, Apache-2.0), and I'd like to derive
Cursor protocol knowledge from this plugin with proper MIT attribution in
our THIRD_PARTY_NOTICES. A LICENSE file in the repo makes that attribution
unambiguous for everyone downstream, not just us.

Thanks!

Start by checking the existing license declaration in package.json and confirming that no LICENSE file is present. Add a standard MIT LICENSE file using the repository's stated copyright holder and verify that its license name matches package.json and provides the complete attribution text.

Written by the indexing model from the issue text.