Add MIT license

LICENSE

@@ -0,0 +1,21 @@
+MIT License
+
+Copyright (c) 2026 Kellen Murphy
+
+Permission is hereby granted, free of charge, to any person obtaining a copy
+of this software and associated documentation files (the "Software"), to deal
+in the Software without restriction, including without limitation the rights
+to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+copies of the Software, and to permit persons to whom the Software is
+furnished to do so, subject to the following conditions:
+
+The above copyright notice and this permission notice shall be included in all
+copies or substantial portions of the Software.
+
+THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
+SOFTWARE.

README.md

@@ -175,4 +175,10 @@ Primarily a personal project and community resource, but bug reports and suggest
 
 ---
 
+## License
+
+[MIT](LICENSE) — free to use, modify, and distribute. Attribution appreciated but not required beyond keeping the copyright notice.
+
+---
+
 Made with ♥ by [The SAML Guy](https://kellenmurphy.com)

SECURITY.md

@@ -98,6 +98,12 @@ The CI workflow enforces test coverage via Vitest and uploads results to Codecov
 
 ---
 
+## License
+
+This project is released under the [MIT License](LICENSE). You are free to use, fork, modify, and distribute the code. The only requirement is that the copyright notice is preserved in copies or substantial portions of the software.
+
+---
+
 ## Out of scope
 
 - Vulnerabilities in tokens or assertions pasted by users — the tool is a decoder, not a validator; it does not make trust decisions on behalf of the user