* Build dropdown menu entries from choice type metadata
* Add a gradient interpolation color space attribute, blending stops in linear light by default
* Add a Space interpolation dropdown to the color picker popover
* Stamp legacy gradient ramps with their implicit gamma interpolation during deserialization
* Resolve color-interpolation from SVG style blocks and fix cascade order among repeated declarations
* Build radio widget entries from choice type metadata so variants display their icons
* Route the node properties enum radio through the shared choice type entry builder
* Rename spread method to gradient spread so it matches the other gradient attribute names
* Keep the legacy gradient struct's spread method field name matching its on-disk key
* Add a spread method field to GradientRamp, carried at runtime as the gradient item's attribute
* Retire the Fill node's spread method input, folding its value into the gradient ramps on document upgrade
* Add an Ends spread method radio to the color picker popover, replacing the Gradient tool's control bar radio
* Update the demo art
* Introduce the GradientRamp exchange struct as the serialized TaggedValue::Gradient payload
* Unify FillChoice and FillChoiceUI into one enum generic over color format, carrying GradientRamp stops
* Rename the TaggedValue::Gradient variant to GradientRamp to match its payload
* Move the Color variant into the tagged_value macro list since its stored and wire forms match
* 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
* Remove the dead InputAccessor traits and the uncallable test helper built on them
* Replace raw node input indices with macro-generated parameter symbols across the editor
* Audit dynamic input index usage, converting to parameter symbols and named input position constants
* Abstract the remaining input index plumbing behind ParameterRef APIs and accessors
* Build SetInputValue messages as struct literals to keep message enums impl-free
* Delete the typed parameter markers in favor of explicit-output test introspection
* Wire the interpolation control path input per chain node type
* Return no input when a parameter symbol is read against the wrong node's parameter view
