docs: collapse sidebar by default in main docs + persist state (#8608)

* docs: collapse sidebar by default in main docs + persist state

* persist sidebar hidden

www/packages/docs-ui/src/components/Sidebar/Item/Category/index.tsx

@@ -23,7 +23,12 @@ export const SidebarItemCategory = ({
     item.initialOpen !== undefined ? item.initialOpen : expandItems
   )
   const childrenRef = useRef<HTMLUListElement>(null)
-  const { isChildrenActive } = useSidebar()
+  const {
+    isChildrenActive,
+    updatePersistedCategoryState,
+    getPersistedCategoryState,
+    persistState,
+  } = useSidebar()
 
   useEffect(() => {
     if (open && !item.loaded) {
@@ -44,6 +49,16 @@ export const SidebarItemCategory = ({
     }
   }, [isChildrenActive])
 
+  useEffect(() => {
+    if (!persistState) {
+      return
+    }
+    const persistedOpen = getPersistedCategoryState(item.title)
+    if (persistedOpen !== undefined) {
+      setOpen(persistedOpen)
+    }
+  }, [persistState])
+
   const handleOpen = () => {
     item.onOpen?.()
   }
@@ -70,6 +85,9 @@ export const SidebarItemCategory = ({
             if (!open) {
               handleOpen()
             }
+            if (persistState) {
+              updatePersistedCategoryState(item.title, !open)
+            }
             setOpen((prev) => !prev)
           }}
         >