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/date-picker-controlled.tsx

@@ -0,0 +1,21 @@
+"use client"
+
+import { DatePicker } from "@medusajs/ui"
+import { useState } from "react"
+
+export default function DatePickerControlled() {
+  const [date, setDate] = useState<Date | null>(new Date())
+
+  return (
+    <div className="space-y-4 w-[300px]">
+      <DatePicker
+        value={date}
+        onChange={setDate}
+        aria-label="Select a date"
+      />
+      <div className="text-ui-fg-subtle text-ui-body-small">
+        Selected date: {date ? date.toLocaleDateString() : "None"}
+      </div>
+    </div>
+  )
+}