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/howtos/code/store/readme.mdx

@@ -0,0 +1,49 @@
+---
+title: Sharing data between parts
+---
+
+Sometimes, you'll want to access data from one part into another part. For
+example, you may store the length of the armhole in your front and back parts,
+and then read that value when drafting the sleeve so you can verify the sleeve
+fits the armhole.
+
+For this, you should use the [Store](/reference/api/store/), which is available
+via _destructuring_ in your part's draft method.
+
+Setting a value in one part:
+
+```mjs
+function draftPartA({
+  // highlight-start
+  store,
+  // highlight-end
+  part,
+}) {
+  // highlight-start
+  store.set('hello', 'world')
+  // highlight-end
+
+  return part()
+}
+```
+
+Reading a value in another part:
+
+```mjs
+function draftPartB({
+  // highlight-start
+  store,
+  // highlight-end
+  part,
+}) {
+  // highlight-start
+  const value = store.get('hello')
+  // value now contains 'world'
+  // highlight-end
+
+  return part()
+}
+```
+
+In a case like this, the order in which parts are drafted becomes important, so you
+should reflect that in the [part dependencies](/howtos/code/after).