Grid (and grid-snap) state was shared through the global show_grid flag, so
toggling it in model space also turned it on in paper space, and a floating
viewport's grid painted across the whole paper — and beyond the 3-D view when
zoomed in.
- Store grid/snap per view: a model tile in model space, the active floating
viewport or the layout's sheet viewport in paper space, round-tripped via the
viewport status flags.
- adopt_view_display on layout switch and viewport enter/exit so the live
toggle follows the view you are in.
- Render one grid per view (paper_viewport_grid_views): the sheet over the
paper, each floating viewport clipped to its screen rectangle.
- Clamp the grid clip to the widget so an overflowing viewport rectangle never
paints grid outside the 3-D view.
Co-Authored-By: Claude Opus 4.8 <[email protected]>
