docs: update BUILDING.md for cursor rules refactoring and build system updates

BUILDING.md

@@ -2679,3 +2679,50 @@ All scripts use consistent error handling:
 **Note**: This documentation is maintained alongside the build system. For the
 most up-to-date information, refer to the actual script files and Vite
 configuration files in the repository.
+
+---
+
+## Build Changes Changelog
+
+### 2025-08-21 - Cursor Rules Refactoring and Build System Updates
+
+#### Package Dependencies Updated
+- **Added**: `markdownlint-cli2` v0.18.1 - Modern markdown linting with improved performance
+- **Added**: `@commitlint/cli` v18.6.1 - Conventional commit message validation
+- **Added**: `@commitlint/config-conventional` v18.6.2 - Conventional commit standards
+- **Updated**: `husky` v9.0.11 - Git hooks management
+- **Updated**: `lint-staged` v15.2.2 - Pre-commit linting automation
+
+#### Build Script Improvements
+- **Markdown Linting**: Replaced custom markdown scripts with `markdownlint-cli2`
+  - **Before**: `./scripts/fix-markdown.sh` and `./scripts/validate-markdown.sh`
+  - **After**: `markdownlint-cli2 --fix` and `markdownlint-cli2`
+  - **Benefits**: Faster execution, better error reporting, modern markdown standards
+
+#### Lint-Staged Configuration Enhanced
+- **Added**: Markdown file linting to pre-commit hooks
+  - **Pattern**: `*.{md,markdown,mdc}` files now automatically formatted
+  - **Command**: `markdownlint-cli2 --fix` runs before each commit
+  - **Coverage**: All markdown files including `.mdc` cursor rules
+
+#### Commit Message Standards
+- **Added**: Conventional commit validation via commitlint
+- **Configuration**: Extends `@commitlint/config-conventional`
+- **Enforcement**: Ensures consistent commit message format across the project
+
+#### Node.js Version Requirements
+- **Updated**: Minimum Node.js version requirements for new dependencies
+- **markdownlint-cli2**: Requires Node.js >=20
+- **Various utilities**: Require Node.js >=18 for modern ES features
+
+#### Build Process Impact
+- **No Breaking Changes**: All existing build commands continue to work
+- **Improved Quality**: Better markdown formatting and commit message standards
+- **Enhanced Automation**: More comprehensive pre-commit validation
+- **Performance**: Faster markdown linting with modern tooling
+
+---
+
+**Note**: This documentation is maintained alongside the build system. For the
+most up-to-date information, refer to the actual script files and Vite
+configuration files in the repository.