Figure out right type for coordinates

Candidates: `Int`, `Float`, `Double`. If all else fails, `Number`.

Look at the Kotlin wrapper code for Pixi.js to see where coordinates are used. Check the Pixi.js documentation for the expected JavaScript types. Determine if Int, Float, Double, or Number is the most appropriate Kotlin type for interoperability. Test changes by running any existing tests or examples.

由索引模型根据 Issue 内容生成。