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/plugins/bust/readme.mdx

@@ -0,0 +1,108 @@
+---
+title: plugin-bust
+---
+
+Published as [@freesewing/plugin-bust][1], this plugin helps you adapt menswear
+patterns for people with breasts.  If you are designing a womenswear pattern,
+you won't need this plugin. But if you're adapting a menswear pattern for
+breasts or merely want to accommodate both people with and without breasts,
+this plugin can help you accomplish that.
+
+## Installation
+
+```bash
+npm install @freesewing/plugin-bust
+```
+
+## Usage
+
+Either [add it as a part plugins](/reference/api/part/config/plugins) in your
+design, or [add it to a pattern instance with
+Pattern.use()](/reference/api/pattern/use).
+
+To import the plugin for use:
+```js
+import { bustPlugin } from '@freesewing/plugin-bust'
+// or
+import { pluginBust } from '@freesewing/plugin-bust'
+```
+
+To import the plugin and condition method for conditional loading:
+```js
+import { withCondition } from '@freesewing/plugin-bust'
+```
+
+## Notes
+
+### Understanding the use-case for this plugin
+
+Almost all menswear patterns use the chest circumference to draft the garment.
+
+As a person with breasts, using your (full) chest circumference will give you
+bad fit.  Instead, it's better to use your high bust measurement as chest
+circumference, and then create extra room for the breasts.
+
+This is the same technique that's used in a full-bust adjustment to fit a
+womenswear pattern for a person with above-average sized breasts.
+
+This plugin helps you by:
+
+- Storing the chest circumference in `measurements.bust`
+- Changing `measurments.chest` to the value of
+  `measurements.highBust`
+
+### Use when extending breastless patterns into a with-breasts version
+
+One way this plugin is used is to extend a menswear pattern into a womenswear
+pattern.  In this case, the plugin will always be loaded since the pattern
+assumes breasts will be present.
+
+This way you can extend a menswear pattern and have it drafted with the high
+bust measurement as chest measurement, after which you can create room for the
+breasts.
+
+You can see this in practice in our [Carlita][2] design, which extends the
+menswear [Carlton][3] design.
+
+:::note RELATED
+To learn more about extending a design, see [Part
+inheritance](/howtos/code/from/)
+:::
+
+### Use when creating gender-neutral designs
+
+To create a truly gender-neutral design — one that will adapt to breasts only
+if they are present — you can use this plugin, but you'll also need a few other
+things:
+
+- You'll need to include and mark the bust measurements, including `highBust`,
+as [optional
+  measurements](/reference/api/part/config/measurements#optionalmeasurements)
+- You'll need to [conditionally load this
+  plugin](/reference/api/part/config/plugins#conditional-plugins)
+- You'll need to create your design such that, when appropriate,
+it is able to produce the condition to cause the plugin to load
+
+You can see an example of this in [our Teagan design][4].
+
+### Condition for loading `withCondition`
+
+For convenience, `plugin-bust` provides a `withCondition` named export
+that is a conditional plugin, an `Object` consisting of the plugin
+along with a condition method.
+
+The condition is met if both:
+1. `options.draftForHighBust` is set to `true`
+2. `measurements.highBust` is set
+
+You can use `withCondition` to conditionally load `plugin-bust`,
+or you are free to instead create and use your own condition method
+to pass along with the plugin.
+
+[1]: https://www.npmjs.com/package/@freesewing/plugin-bust
+
+[2]: https://github.com/freesewing/freesewing/blob/develop/designs/carlita/src/index.mjs#L25
+
+[3]: https://github.com/freesewing/freesewing/blob/develop/designs/carlton
+
+[4]: https://github.com/freesewing/freesewing/blob/develop/designs/teagan/src/index.mjs