Add the "Perceptual" and "Classic" families of gradient spaces with OkLab as the new default (#4415)

* Add an OkLab gradient interpolation space and make it the new default

* Fix the Properties panel fill row resetting the gradient interpolation space to the default

* Add OkLch, Lab, LCh, and HSL gradient interpolation spaces

* Add a hue direction attribute and picker choice for polar gradient interpolation spaces

* Add an HSV gradient interpolation space

* Rename the sRGB Linear and sRGB Gamma gradient spaces to RGB Linear and RGB Gamma

* Divide the gradient interpolation dropdown between absolute and relative color spaces

* Rename the OkLch gradient interpolation space to OkLCh for channel-notation capitalization

* Shorten the color picker popover's hue direction row label to Arc

* Call the Gradient Interpolation node's parameter Space and extend the picker tooltip title to match

* Rename the gradient interpolation attribute and type family to gradient space

* Rename the gradient tool's gradient space transform to gradient to viewport transform

* Add serde aliases and a node replacement covering the gradient space renames

* Give the gradient space choices artist-facing labels and reorder the dropdown sections

* Add a Gradient Hue Direction node and its attribute read node

* Say interpolate instead of blend for gradient stop color traversal in docs and tooltips

* Label the polar perceptual gradient spaces as Perceptual Hue and group the dropdown sections by geometry

* Add a migration alias covering the gradient space attribute reader rename

* Carry the gradient hue direction attribute through boolean operations

* Register GradientHueDirection wire types in the node registry

node-graph/nodes/graphic/src/graphic.rs

@@ -9,7 +9,7 @@ use rand::SeedableRng;
 use rand::seq::SliceRandom;
 use raster_types::{CPU, GPU, Raster};
 use std::cmp::Ordering;
-use vector_types::gradient::{GradientForm, GradientInterpolation, GradientSpread};
+use vector_types::gradient::{GradientForm, GradientHueDirection, GradientSpace, GradientSpread};
 use vector_types::{Gradient, ReferencePoint};
 
 /// Returns the list with the item at the specified index removed.
@@ -747,18 +747,35 @@ fn read_attribute_gradient_spread(
 	result
 }
 
-/// Reads a named `GradientInterpolation` attribute from the input list, outputting each value as an element of a new `GradientInterpolation[]`.
+/// Reads a named `GradientSpace` attribute from the input list, outputting each value as an element of a new `GradientSpace[]`.
 #[node_macro::node(category("Attributes: Read"))]
-fn read_attribute_gradient_interpolation(
+fn read_attribute_gradient_space(
 	_: impl Ctx,
 	content: ListDyn,
 	/// The attribute name (key) to read.
 	name: Item<String>,
-) -> List<GradientInterpolation> {
+) -> List<GradientSpace> {
 	let name = name.into_element();
 	let mut result = List::with_capacity(content.len());
 	for index in 0..content.len() {
-		let Some(value) = content.attribute::<GradientInterpolation>(&name, index) else { continue };
+		let Some(value) = content.attribute::<GradientSpace>(&name, index) else { continue };
+		result.push(Item::new_from_element(*value));
+	}
+	result
+}
+
+/// Reads a named `GradientHueDirection` attribute from the input list, outputting each value as an element of a new `GradientHueDirection[]`.
+#[node_macro::node(category("Attributes: Read"))]
+fn read_attribute_gradient_hue_direction(
+	_: impl Ctx,
+	content: ListDyn,
+	/// The attribute name (key) to read.
+	name: Item<String>,
+) -> List<GradientHueDirection> {
+	let name = name.into_element();
+	let mut result = List::with_capacity(content.len());
+	for index in 0..content.len() {
+		let Some(value) = content.attribute::<GradientHueDirection>(&name, index) else { continue };
 		result.push(Item::new_from_element(*value));
 	}
 	result