Expanding the Vega engine to support the analysis of multidimensional data

This project aims to extend the plot module by implementing the missing building blocks needed for end-to-end chart creation. The work will focus on improving how data is mapped to visual representations, adding support for a broader range of visual elements, and enabling better composition of charts. Additionally, the project will introduce features for interactivity, layout management, and common data processing operations, making the API more practical for real-world usage. Each component will be developed with proper testing, documentation, and performance considerations to ensure reliability and consistency with the stdlib ecosystem. By the end of the project, users will be able to programmatically generate complete and reusable visualization specifications using a modular JavaScript API, without relying on manually written JSON.