docs: migrate UI docs (#13245)

* docs: create a new UI docs project (#13233)

* docs: create a new UI docs project

* fix installation errors

* docs: migrate UI docs content to new project (#13241)

* Fix content

* added examples for some components

* finish adding examples

* lint fix

* fix build errors

* delete empty files

* path fixes + refactor

* fix build error

www/apps/ui/specs/examples/textarea-controlled.tsx

@@ -0,0 +1,19 @@
+import { useState } from "react"
+import { Textarea } from "@medusajs/ui"
+
+export default function TextareaControlled() {
+  const [value, setValue] = useState("")
+  return (
+    <div className="flex flex-col gap-y-2">
+      <Textarea
+        value={value}
+        onChange={(e) => setValue(e.target.value)}
+        placeholder="Write your feedback..."
+        aria-label="Feedback"
+      />
+      <div className="text-ui-fg-muted txt-compact-small">
+        {value.length} characters
+      </div>
+    </div>
+  )
+}