Add object collision and self collision feature to sculpt brushes

Currently, Blender’s Cloth Brushes are capable of handling collisions with other meshes. However, regular Sculpt Brushes do not have this capability, which often leads to unwanted self-intersections or mesh penetrations during sculpting.

Proposal:

Add Object Collision and Self-Collision options to the Sculpt Brush tool settings, similar to what already exists in the Cloth Brush system. This would allow sculptors to work with physical thickness awareness and prevent geometry from collapsing or intersecting itself unintentionally.

Suggested settings:

-Enable Collision: Toggle for detecting other objects in the scene.

-Enable Self-Collision: Toggle for detecting and resolving intersections within the same mesh.

-Thickness: A small adjustable offset to define how close vertices can get before being repelled.

In this model, we can avoid self intersection with move brush that has self collision enabled.

For comparison, Differential Growth and similar procedural simulations demonstrate natural self-collision handling when expanding geometry, something we currently lack in manual sculpting workflows.