chore: Port FreeSewing.dev to docusaurus

The replaces the NextJS site powering FreeSewing.dev with a Docusaurus
setup. It's part of my efforts to simplify FreeSewing's setup so we can
focus on our core value proposition.

sites/dev/docs/reference/api/utils/curvesintersect/readme.mdx

@@ -0,0 +1,82 @@
+---
+title: utils.curvesIntersect()
+---
+
+The `utils.curvesIntersect()` function finds the intersections between two curves
+described by 4 points each.
+
+:::warning
+
+This function can sometimes fail to find intersections in some curves
+due to a limitation in an underlying Bézier library.
+Please see [Bug #3367](https://github.com/freesewing/freesewing/issues/3367)
+for more information.
+
+:::
+
+## Signature
+
+```js
+array | Point | false utils.curvesIntersect(
+  Point startA,
+  Point Cp1A,
+  Point Cp2A,
+  Point endA,
+  Point startB,
+  Point Cp1B,
+  Point Cp2B,
+  Point endB)
+```
+
+This returns `false` if no intersections are found,
+a [Point](/reference/api/point) object if
+a single intersection is found, and an array
+of [Point](/reference/api/point) objects if
+multiple intersections are found.
+
+## Example
+
+<Example caption="A Utils.curvesIntersect() example">
+```js
+({ Point, points, Path, paths, Snippet, snippets, utils, getId, part }) => {
+
+  points.A = new Point(10, 10)
+  points.Acp = new Point(310, 40)
+  points.B = new Point(110, 70)
+  points.Bcp = new Point(-210, 40)
+
+  points.C = new Point(20, -5)
+  points.Ccp = new Point(60, 300)
+  points.D = new Point(100, 85)
+  points.Dcp = new Point(70, -220)
+  paths.curveA = new Path()
+    .move(points.A)
+    .curve(points.Acp, points.Bcp, points.B)
+  paths.curveB = new Path()
+    .move(points.C)
+    .curve(points.Ccp, points.Dcp, points.D)
+
+  const intersections = utils.curvesIntersect(
+    points.A,
+    points.Acp,
+    points.Bcp,
+    points.B,
+    points.C,
+    points.Ccp,
+    points.Dcp,
+    points.D
+    )
+
+  if (intersections) {
+    if (intersections instanceof Array) {
+      for (const p of intersections)
+        snippets[getId()] = new Snippet('notch', p)
+    } else {
+      snippets[getId()] = new Snippet('notch', intersections)
+    }
+  }
+
+  return part
+}
+```
+</Example>