Add Khronos PBR Neutral tone mapper

A tone mapper designed specifically for PBR color accuracy, to get sRGB
colors in the output render that match as faithfully as possible the input
sRGB baseColor under gray-scale lighting. This is aimed toward product
photography use cases, where the scene is well-exposed and HDR color values
are mostly restricted to small specular highlights.

Fixes #118824: Proposal: add a view transform for Khronos PBR Neutral Tone Mapper

Co-authored-by: Emmett Lalish <elalish@google.com>
Pull Request: https://projects.blender.org/blender/blender/pulls/118936

scripts/startup/bl_ui/properties_render.py

@@ -113,7 +113,8 @@ class RENDER_PT_color_management_display_settings(RenderButtonsPanel, Panel):
         col = layout.column(align=True)
         sub = col.row()
         sub.active = (not view.view_transform.startswith("Filmic") and not view.view_transform.startswith("AgX") and not
-                      view.view_transform.startswith("False Color"))
+                      view.view_transform.startswith("False Color") and not 
+                      view.view_transform.startswith("Khronos PBR Neutral"))
         sub.prop(view, "use_hdr_view")