Repacking textures with bleed ring.

[dknezevic]

Adds a 2px bleed ring around textures when repacking.
This removes "cracks" which can occur when zooming out.
Currently it is fixed to 2px, but it makes sense to increase it for larger textures with the formula similar to this:
width<2^10 => 0
width > 2^10 => 2^(log2(width)-10)

e.g:
512x512 => 0px
1024x1024 =>2px
2048x2048 => 4px
etc.

This is implementation of #4 and probabbly fixes #38

[Copilot]

Pull Request Overview

This PR implements texture bleeding/padding functionality to prevent rendering "cracks" that occur when zooming out from repacked textures. The implementation adds a 2-pixel bleed ring around each texture chart during the repacking process.

• Adds a 2px bleed ring around textures during repacking to prevent visual artifacts
• Refactors UV coordinate calculations and UDIM tile handling for better precision
• Introduces a new BuildPaddedBlock method that creates padded texture charts by duplicating edge pixels

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[HeDo88TH]

Looks go to me 🚀