irisandClaude Sonnet
1a6599e1b2
Implements LAYOUT.md end to end: one fn draw(&mut self, &mut Painter) -> Size replaces draw + desired_width/desired_height on every widget in iris/src/widget/, SizeCtx and Cache are deleted, and a moved widget (Scroll, Offset) costs one move_offsets write resolved by a shared resolve_move WGSL function in both shader stages -- O(1) regardless of how many primitives are in its subtree, measured at 500 in the new iris/src/layout_tests.rs (a plain unit test: UiRenderState touches no GPU or window). Five real bugs surfaced only by diffing iris/run-headless.sh screenshots against the pre-change tree and are written up in LAYOUT.md's "Deviations found during implementation": Aligned's provisional draw composing painter.region() a second time through widget_within; Sized/ MaxSize reporting a capped size while still painting their child unconstrained (fine under the old two-pass model, wrong once a parent like Aligned draws before knowing the final size); a widget's move_offsets parent link being unreadable from self.active while its own ActiveData is still mid-construction; Painter::reposition needing the child's *painted* footprint (its reported size, top-left anchored) rather than its offered region; and a widget's move slot needing to be reused in place across redraws, with its delta reset, rather than reallocated. All four iris/examples render pixel-identical to the pre-change tree. cargo fmt/clippy/test clean across the workspace (18 tests: 14 pre-existing plus 4 new). Co-Authored-By: Claude Sonnet <noreply@anthropic.com>