Use $app/stores for subNavigation reactivity in shell.svelte

The $app/state page proxy was not properly triggering $: reactive
statements during client-side navigation. Switch to the store-based
$page from $app/stores which has reliable reactivity tracking in
Svelte legacy mode.

https://claude.ai/code/session_012QCz2xVatAtJ3Q6FSp1cB4

Author: claude

src/lib/layout/shell.svelte

@@ -15,6 +15,7 @@
     import { hasOnboardingDismissed } from '$lib/helpers/onboarding';
     import { isSidebarOpen, noWidthTransition } from '$lib/stores/sidebar';
     import { page } from '$app/state';
+    import { page as pageStore } from '$app/stores';
     import { BillingPlanGroup, type Models } from '@appwrite.io/console';
     import { getSidebarState, isInDatabasesRoute, updateSidebarState } from '$lib/helpers/sidebar';
     import { isTabletViewport } from '$lib/stores/viewport';
@@ -191,7 +192,7 @@
 
     $: state = $isSidebarOpen ? 'open' : 'closed';
 
-    $: subNavigation = page.data.subNavigation;
+    $: subNavigation = $pageStore.data.subNavigation;
 
     $: shouldRenderSidebar =
         !$isNewWizardStatusOpen && showSideNavigation && !$showOnboardingAnimation;