Revert "feat: add calendar frontend"

This reverts commit af83a68fe1.

frontend/e2e/backup-roundtrip.spec.ts

@@ -8,11 +8,6 @@ function bottomTab(page: Page, name: string) {
   return page.getByRole('navigation', { name: '主要导航' }).getByRole('button', { name, exact: true })
 }
 
-async function openSidebarView(page: Page, name: string) {
-  await page.getByRole('button', { name: /展开菜单|收起菜单/ }).click()
-  await page.locator('.sidebar').getByRole('button', { name, exact: true }).click()
-}
-
 async function csrf(request: APIRequestContext, baseURL: string) {
   const state = await request.storageState()
   return state.cookies.find(cookie => cookie.name === 'dodo_csrf' && baseURL.includes(cookie.domain))?.value
@@ -55,7 +50,7 @@ test('complete ZIP backup preflights and replace-restores task, habit history, c
   expect(countdownResponse.ok()).toBeTruthy()
 
   await page.goto('/')
-  await openSidebarView(page, '设置')
+  await bottomTab(page, '设置').click()
   const downloadPromise = page.waitForEvent('download')
   await page.getByRole('button', { name: '导出 ZIP' }).click()
   const download = await downloadPromise