Remove CI workflow configuration

The GitHub Actions CI workflow has been removed as this is a learning demo
focused on local MCP server development rather than production deployment.
All 7 tools, 3 prompts, and 4 resources have been verified working with
MCP Inspector CLI testing.

🤖 Generated with [Claude Code](https://claude.ai/code)

Co-Authored-By: Claude <noreply@anthropic.com>

Author: yigitkonur