Validate series data points against categorical axis categories

[korvin89]

Currently, when an axis (X or Y) is configured with type: 'category', there is no validation to ensure that the data points in the series correctly reference the defined categories.

We should add a check that iterates through all data points and verifies that:

• If a coordinate is a number, it must be a valid index within the categories array range.
• If a coordinate is a string, it must be present in the categories array.

This validation will help developers catch configuration errors (such as typos or out-of-bounds indices) early and avoid empty or broken charts.