feat: add procedural Vertex Color Bake tool

[cs-dev-09]

Description
This adds a new "Vertex Color Bake" tool to the addon, designed specifically for procedurally generating vertex colors (Color 1) for GTA V props. The panel has been integrated into the N-Panel under the Surface group.

Key Features:

• Detail Stack: Allows artists to procedurally bake and blend multiple layers of environmental wear:
  • Ambient Occlusion (Raytraced)
  • Edge Dirt (Concave edge detection)
  • Floor Grime (Z-up surface spread)
  • Edge Wear (Convex edge detection)
  • Fake Directional Shadows
  • Linear Gradients & Random Noise
• Performance Optimized: Expensive geometry operations (like AO raycasting and edge-angle detection) are cached on the mesh. Adjusting the UI strength sliders only re-blends the cached data, making the UI incredibly fast and responsive even on dense meshes.
• Non-Destructive Alpha: The tool cleanly targets RGB while intelligently blending the alpha channel, ensuring existing vertex setups aren't accidentally destroyed.

UI Integration:

• Registered as an independent module (vertex_bake).
• Panel sits at the bottom of the "Surface" section, utilizing the existing toolset's UI conventions and icon library.
• Default slider values have been tuned for instant, usable results on typical GTA V assets.