fix(layout): migrate isSidebarCollapsed persistence from sessionStorage to localStorage

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

src/stores/layout.ts

@@ -127,11 +127,7 @@ export const useLayoutStore = defineStore(
   {
     persist: [
       {
-        pick: ['isSidebarCollapsed'],
-        storage: sessionStorage,
-      },
-      {
-        pick: ['screenshotMobileAdapt', 'isToolsPanelLocked', 'isToolsPanelMini', 'toolsPanelPosition'],
+        pick: ['isSidebarCollapsed', 'screenshotMobileAdapt', 'isToolsPanelLocked', 'isToolsPanelMini', 'toolsPanelPosition'],
         storage: localStorage,
       },
     ],