Production crash where @(get bounds id) threw
"No protocol method IDeref.-deref defined for type null"
when a shape ID had no corresponding entry in the bounds map
during layout calculations.
Added defensive nil guards (when-let / when) to all unprotected
bounds dereference sites:
- flex_layout/bounds.cljc: layout-content-points (parent + child)
and layout-content-bounds
- grid_layout/bounds.cljc: layout-content-points and
layout-content-bounds
- min_size_layout.cljc: child-min-width grid branch (3 sites) and
child-min-height grid branch
Added 7 new tests in geom_bounds_layout_nil_test.cljc covering all
nil-bounds edge cases for flex, grid, and min-size layout paths.
Registered in runner.cljc.
Closes#10843
AI-assisted-by: qwen3.7-plus
