Replace the custom model_tiles tiling with iced 0.14 pane_grid as the layout
source of truth, while paper-space floating viewports are left untouched (they
overlap/free-place, which pane_grid cannot model).
Each Model pane is its own shader widget rendering its camera into the pane
bounds; the renderer Primitive carries a base_slot so several shader widgets
share the type-keyed MultiPipeline storage on disjoint slots. A second pane_grid
of transparent mouse_areas (plus on_resize) layers above the crosshair overlay
to receive input — the overlay's Hidden cursor interaction otherwise levitates
the cursor and starves any layer beneath it. The active pane follows the cursor
(hover-activate), and grid / crosshair / UCS icon render per pane while the
ViewCube and render-mode picker stay on the active pane only.
Split / close / VPORTS presets and the VPort table round-trip now drive
pane_grid (guillotine reconstruction on load). Adds drag-to-swap via a controls
bar handle with a ghost-card preview, visible pane dividers from the pane_grid
split regions, a default model background of RGB(33,40,48), and removes all the
superseded custom-tile code.
Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>
Move the 30 flat modules under src/scene/ into six folders by role:
convert (entity→geometry), text (fonts/shaping), model (render models),
pick (hit-test/selection/grips/xclip), view (camera/transform/render),
cache (block + property caches). pipeline/ is unchanged.
Full path migration — all `scene::X` references become
`scene::<group>::X`, no compatibility re-exports. render.rs items that
were `pub(super)` (parent was scene) become `pub(in crate::scene)` to
keep their original scene-wide visibility.
No behavior change; build and tests are green.
Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>
