Stipple's runtime core.

Defines the declarative [View] trait, the [Element] IR that views build, and the layout + paint passes ([render_view]) that turn a view into a [Scene] ready for stipple-render to rasterize.

Pipeline

build → layout → paint, with pointer events routed back through the laid- out tree:

• a [View] (or an app build closure with a [Cx]) produces an [Element] tree, registering on_tap handlers in the context;
• [layout] turns it into a retained [LayoutNode] tree;
• [paint] draws that tree into a [Scene], and [hit_test] routes pointer taps to the registered [Handlers].

Between frames, [diff_trees] reconciles the previously-presented [LayoutNode] tree against the freshly built one to compute the changed [Damage] region, so the platform re-presents only what moved rather than the whole window.

Still ahead (ROADMAP.md Phase 1+): fine-grained per-node state so a rebuild can skip unchanged subtrees entirely, and richer gesture recognition.