fix(HEL-240): 去掉登录页底部状态栏缺口

登录页覆盖全局 body 底边距，让左栏品牌面板铺满视口高度。

Co-authored-by: Cursor <cursoragent@cursor.com>
Co-authored-by: multica-agent <github@multica.ai>

tests/e2e/login-portal.spec.js

@@ -190,6 +190,7 @@ async function assertConfirmedSkeleton(page, { width, height }) {
   if (width === 1440) {
     expect(brand.width).toBeGreaterThan(470);
     expect(brand.width).toBeLessThan(520);
+    expect(brand.height).toBe(height);
   } else if (width === 1920) {
     expect(brand.width).toBeGreaterThan(540);
     expect(brand.width).toBeLessThan(580);