chore: bump version to 0.2.8 and update changelog

docs: update changelog for v0.2.7

feat: add skills management functionality

- Introduced a new module for managing skills, allowing users to create, list, and show skill files.
- Implemented skills initialization to scaffold the necessary directory structure and README.
- Added functionality to load skills from disk and register them as dynamic MCP tools.
- Enhanced the HIEF server to support executing skills and retrieving their content.
- Updated the server's command handling to include new skills commands.
- Added validation for skill names to prevent security issues.
- Introduced tests for skills management to ensure functionality and correctness.

feat: Implement GitHub Actions workflow for automated multi-platform …

…releases and update the active development context file.