* Rework Gradient into a newtype of List<Color> with optional position and midpoint attributes
* Fix Vello stopless-gradient fallback coverage, empty legacy gradient tables, the node docs gradient swatch, NaN position elision, and wired setter input overwrites
* Feature-gate serde derives behind cfg_attr in all runtime node graph type crates
* Refactor Table to move its hard-coded fields into an attributes field
* Encapsulate TableRow/TableRowRef/TableRowMut attribute fields behind accessor methods
* Remove TaggedValue::GraphicUnused
* Refactor Table<T> to use dynamic attributes instead fixed names
* Fix code review soundness concerns
* Add todo work
* Replace row-oriented Table<T> API with column-oriented access
* Fix attribute propagation bugs
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* Refactor GradientStops to use struct-of-arrays and include midpoint
* Implement interaction and rendering
* Make color picker saturation-value color picking snap to original position and show both axis lines
Make color picker saturation-value color picking snap to original position and show both axis lines
* Add graphite:midpoint attribute to SVG exports
* Add graphite:midpoint parsing to SVG importer