Major overhaul of native wrapper generation for ufbx and nvtt.
Replaces all hand-written and class-based wrappers with auto-generated partial struct wrappers that directly expose native API methods via pointers. Introduces a new JSON-driven configuration system using "remaps" and "actions" for flexible parameter/return mapping and method routing. Removes legacy config sections and helper classes, focusing solely on method wrappers. Updates all usages and tests to use the new pointer-based API. Cleans up obsolete code and ensures resource management is handled via struct Dispose methods. The result is a thinner, more direct, and maintainable interop layer.
BREAKING CHANGE: All managed wrapper classes and helpers are removed in favor of struct-based pointer wrappers. API usage and resource management patterns have changed.