refactor(ugc): remove the path traced hidden-face method; the renders are the only one

The path tracer that imitated LU Toolbox's Remove Hidden Faces took 17 to 100
times as long as the renders from 42 directions around the model, too heavy to
use. It goes with its settings (hsr_method, hsr_samples, hsr_bounces,
hsr_sample_spacing, hsr_min_points), its side by side tracing for GPUs and its
tests. The renders (UgcRender::VisibleFromAround) remove hidden faces as before
that method existed; their size is hsr_resolution (1024), and the memory
estimate counts their buffers again.

The hidden-face method is no longer a processing option: the dashboard's picker,
/reprocessproperty and --make-model take only the ray backend (the occlusion's)
and denoising. Options stored before (made_options, process_options,
ugc_process_runs, --make-model arguments) that name toolbox or fast still
parse; the word is skipped.

Check: the settings page has no hsr_method or path settings and has
hsr_resolution; /reprocessproperty embree toolbox still works (toolbox
ignored); models made with the defaults keep their hashes (UGC tests).

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

dUgcServer/Render/UgcRays.cpp

@@ -21,8 +21,7 @@ namespace {
 	using UgcRays::INF;
 
 	/**
-	 * A bounding volume hierarchy (binned surface area heuristic) over a mesh's triangles, for the paths' rays: the
-	 * nearest hit. A ray never hits the triangle it leaves (`skip`), as in Cycles.
+	 * A bounding volume hierarchy (binned surface area heuristic) over a mesh's triangles, for the nearest hit. A ray never hits the triangle it leaves (`skip`), as in Cycles.
 	 */
 	class ClosestBvh {
 	public: