Bonsai: draw georef gizmo above 3D model geometry

The georef orientation gizmo (crosshair, project-north arrow,
grid-north arrow, true-north arrow, WCS leader) is a coordinate-
system overlay: its purpose is to communicate orientation regardless
of what the model contains, so it must remain visible regardless of
whether 3D geometry occupies the gizmo's z=0 footprint.

Wrap GeoreferenceDecorator.draw_geometry's draw cycle in a
gpu.state.depth_test_set("ALWAYS") / restore pair so the overlay
draws on top of any 3D geometry between the camera and the gizmo.
Matches the precedent set by the dashed-line overlay in
bim/module/model/opening.py.

Generated with the assistance of an AI coding tool.

src/bonsai/bonsai/bim/module/georeference/decorator.py

@@ -180,6 +180,10 @@ class GeoreferenceDecorator(tool.Blender.ViewportDecorator):
         decorator_color_error = self.addon_prefs.decorator_color_error
 
         gpu.state.blend_set("ALPHA")
+        # The georef gizmo is a coordinate-system overlay: it must communicate
+        # orientation regardless of model contents, so depth testing is bypassed.
+        original_depth_test = gpu.state.depth_test_get()
+        gpu.state.depth_test_set("ALWAYS")
 
         self.line_shader = gpu.shader.from_builtin("POLYLINE_UNIFORM_COLOR")
         self.line_shader.bind()  # required to be able to change uniforms of the shader
@@ -318,6 +322,8 @@ class GeoreferenceDecorator(tool.Blender.ViewportDecorator):
                 self.draw_batch("LINES", verts, decorator_color_special, edges)
                 self.draw_dashed_line(location * 3, location * 6, decorator_color_error)
 
+        gpu.state.depth_test_set(original_depth_test)
+
     def draw_dashed_line(self, start, end, colour, should_scale=True):
         direction = (end - start).normalized()
         distance = (end - start).length