feat: Dashboard redesign, plan permissions, and help docs improvements

Major updates including:
- Customizable dashboard with drag-and-drop widget grid layout
- Plan-based feature locking for plugins and tasks
- Comprehensive help documentation updates across all pages
- Plugin seeding in deployment process for all tenants
- Permission synchronization system for subscription plans
- QuotaOverageModal component and enhanced UX flows

🤖 Generated with [Claude Code](https://claude.com/claude-code)

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

frontend/src/hooks/usePlatformSettings.ts

@@ -243,3 +243,15 @@ export const useSyncPlansWithStripe = () => {
     },
   });
 };
+
+/**
+ * Hook to sync a plan's permissions to all tenants on that plan
+ */
+export const useSyncPlanToTenants = () => {
+  return useMutation({
+    mutationFn: async (planId: number) => {
+      const { data } = await apiClient.post(`/platform/subscription-plans/${planId}/sync_tenants/`);
+      return data as { message: string; tenant_count: number };
+    },
+  });
+};