feat: add sync_local_repository tool for syncing local directories to GitHub

This new tool allows MCP clients to:
- Sync a local directory to a GitHub repository in a single commit
- Automatically create the repository if it doesn't exist
- Respect .gitignore patterns and skip binary files
- Configure max file count (default 100, max 500)

Use case: Enable AI assistants to push local codebases to GitHub without requiring git CLI.

Author: Calvin-Francis