[Feature]: Enhance text embossing with grayscale height mapping

[chrisreddington]

Description

Currently, the text rendering in gh-skyline uses a binary threshold for pixel values when creating the 3D text geometry. This results in a "hard" embossing effect where pixels are either fully raised or not at all. We can improve the visual quality by using the pixel's grayscale/whiteness value to determine the embossing height, which would preserve font anti-aliasing in the 3D output.

Requirements

• Modify the text rendering logic to use pixel whiteness values (0-1) to scale embossing height
• Update isPixelActive() to return a float value representing pixel intensity instead of boolean
• Scale the voxel depth based on the pixel intensity value
• Maintain backward compatibility with existing cube generation functions
• Handle edge cases (completely black/white pixels) appropriately

Definition of Done

• Text rendering uses grayscale values to determine embossing height
• Anti-aliased edges of text are preserved in the 3D output
• Documentation is updated to reflect the new behavior
• Unit tests cover various pixel intensity scenarios
• Visual regression tests show improved quality at text edges

Additional Notes

• Consider adding a configuration option to toggle between binary and grayscale modes
• Pixel intensity calculation should account for RGB channels appropriately
• May need to adjust overall embossing depth to maintain visual balance
• Consider impact on STL file size due to increased geometry complexity