VR: Location Scouting

This feature commit implements VR Location Scouting within Blender,
allowing the user to block camera vantage points while immersed in VR.

For feature design, see:

- VR: Location Scouting (!141089): https://projects.blender.org/blender/blender/issues/141089
- VR Location Scouting - high fidelity UI (#143061): https://projects.blender.org/blender/blender/issues/143061
- Design Session on Devtalk: https://devtalk.blender.org/t/2025-06-19-design-session-vr-location-scouting/41135

For up to date screenshots, demos and discussion regarding the feature,
see the following devtalk feedback thread:
https://devtalk.blender.org/t/vr-location-scouting-feedback-and-discussion/44744

Pull Request: https://projects.blender.org/blender/blender/pulls/143945

scripts/modules/bl_keymap_utils/keymap_hierarchy.py

@@ -126,6 +126,7 @@ _km_hierarchy = [
         ('View3D Move Modal', 'EMPTY', 'WINDOW', []),
         ('View3D Zoom Modal', 'EMPTY', 'WINDOW', []),
         ('View3D Dolly Modal', 'EMPTY', 'WINDOW', []),
+        ('View3D VR Location Scouting Capture Review Modal', 'EMPTY', 'WINDOW', []),
 
         # toolbar and properties
         ('3D View Generic', 'VIEW_3D', 'WINDOW', [