Setup MCP Server Integration

Implement MCP server support according to specification at https://github.com/modelcontextprotocol/servers

Tasks:
- [ ] Create MCP client module
- [ ] Implement server connection handling
- [ ] Add server configuration UI
- [ ] Implement protocol methods
- [ ] Add error handling
- [ ] Write tests
- [ ] Add documentation

References:
- MCP Specification
- Tauri IPC documentation