docs: update changelog and fix LICENSE references

- Update CHANGELOG.md with recent fixes and changes
- Fix LICENSE link in README.md (LICENSE -> LICENSE.md)
- Document integer overflow fixes and CLI parsing improvements
- Record removal of _bmad directories

Author: LessUp

CHANGELOG.md

@@ -13,11 +13,22 @@ The format follows [Keep a Changelog](https://keepachangelog.com/en/1.1.0/) and
 
 ## [Unreleased]
 
+### Fixed
+- Integer overflow risk in `verify.cuh` and `tensor_core_sgemm.cuh` for large matrices (use `size_t`)
+- Command-line parsing now uses `strtol()` with proper error handling instead of `atoi()`
+
 ### Changed
 - Consolidated repository governance around `openspec/specs/`, updated agent instructions, and simplified documentation roles.
 - Reworked README, GitHub Pages content, and supporting docs into clearer repository-entry and learning surfaces.
 - Began pruning redundant release-history and engineering guidance artifacts in favor of fewer authoritative files.
 
+### Removed
+- Duplicate `LICENSE` file (kept `LICENSE.md` with third-party info)
+- Legacy `_bmad/` and `_bmad-output/` directories (replaced by OpenSpec)
+
+### Added
+- `.clang-tidy` configuration for static analysis
+
 ## [2.1.0] - 2026-04-16
 
 ### Added

README.md

@@ -2,7 +2,7 @@
 
 [![CI](https://github.com/LessUp/sgemm-optimization/actions/workflows/ci.yml/badge.svg)](https://github.com/LessUp/sgemm-optimization/actions/workflows/ci.yml)
 [![Pages](https://github.com/LessUp/sgemm-optimization/actions/workflows/pages.yml/badge.svg)](https://lessup.github.io/sgemm-optimization/)
-[![License: MIT](https://img.shields.io/badge/License-MIT-blue.svg)](LICENSE)
+[![License: MIT](https://img.shields.io/badge/License-MIT-blue.svg)](LICENSE.md)
 ![CUDA](https://img.shields.io/badge/CUDA-11.0+-76B900?logo=nvidia&logoColor=white)
 ![C++](https://img.shields.io/badge/C%2B%2B-17-00599C?logo=c%2B%2B&logoColor=white)
 
@@ -90,4 +90,4 @@ The stable authoritative specs live under `openspec/specs/`. Active implementati
 
 ## License
 
-MIT. See [LICENSE](LICENSE).
+MIT. See [LICENSE.md](LICENSE.md).