Add Java2D bitmap filter support with convolution operations

[untainsYD]

Implements bitmap-based image filtering for Java2d backend using BufferedImage and ConvolveOp.

Adds support for:

• Gaussian blur with configurable standard deviation.
• Box blur with radius parameter.
• Edge detection using convolution kernels.
• Sharpen filter with adjustable intensity.
• Emboss effect.
• Drop shadow simple version.
• Custom convolution matrix operations.

TODO dropShadow

Java2d drop shadow is complex and requires multiple In this PR is a simplified implementation - full implementation would need:

1. Extract alpha channel as shadow.
2. Apply blur to shadow.
3. Offset shadow.
4. Colorize shadow.
5. Composite original over shadow.

For now, we'll implement a basic version

[untainsYD]

@noelwelsh i have some issues with rendering, need your review.
The core problem seems to be in the transformToBufferedImage method.

p.s.: tests are failing, I know it

[untainsYD]

It is still cropping images and some tests failed, but some progress has been made. I will investigate further.