Bezier-rs: Add joins and caps to offsets and outlines (#1083)

* Intial work

* Improve miter and add round join

* Get arcs to go opposite direction

* Add cap and other refactors

* Rename joint to join, fix some bugs

* Fix single point issue

* Clean up

* Fix iframe sizes and update UI

* Address comments and handle single point outline

* Rename variables, fix branches in outline

* Address comments

website/other/bezier-rs-demos/src/utils/options.ts

@@ -45,3 +45,17 @@ export const subpathTValueVariantOptions = {
 	inputType: "dropdown",
 	options: SUBPATH_T_VALUE_VARIANTS,
 };
+
+export const joinOptions = {
+	variable: "join",
+	default: 0,
+	inputType: "dropdown",
+	options: ["Bevel", "Miter", "Round"],
+};
+
+export const capOptions = {
+	variable: "cap",
+	default: 0,
+	inputType: "dropdown",
+	options: ["Butt", "Round", "Square"],
+};