Release v0.2.8

[Hk669]

This pull request updates the project to version 0.2.8, introducing new features and enhancements to documentation, search functionality, and performance optimizations.

Feature additions:

• Added term linking functionality to improve relationships between glossary terms.
• Enhanced the search tool with popularity attributes, context, and examples for better usability.
• Added comprehensive documentation for MCP transport modes.

Performance and configuration improvements:

• Implemented a client singleton pattern to optimize connection pool reuse and overall performance.
• Improved Docker configuration by updating .dockerignore settings for better container management.

Other updates:

• Bumped the project version to 0.2.8 in modelcontextprotocol/version.py.

[Hk669]

@firecast lets merge #91 before the release.