refactor: extract empty state and update basepath to /app/

Signed-off-by: Noa Virellia <noa@requiem.garden>

client/cms/src/stories/events/event-grid.stories.tsx

@@ -60,14 +60,25 @@ export const Primary: Story = {
         endTime: new Date('2026-06-14T04:00:00.000Z'),
       },
     ],
-    assembleFooter: () => <Button className="w-full">加入活动</Button>,
+    footer: () => <Button className="w-full">加入活动</Button>,
   },
 };
 
-export const Skeleton: Story = {
+export const Empty: Story = {
+  decorators: [Story => <div className="h-screen">{Story()}</div>],
+  args: {
+    events: [],
+    footer: () => <Button className="w-full">加入活动</Button>,
+  },
+  parameters: {
+    layout: 'fullscreen',
+  },
+};
+
+export const Loading: Story = {
   render: () => <EventGridSkeleton />,
   args: {
     events: [],
-    assembleFooter: () => <UiSkeleton className="w-full" />,
+    footer: () => <UiSkeleton className="w-full" />,
   },
 };