feat(web): connect quick share flow

Signed-off-by: JustMe <mr.toing@outlook.com>

web/src/features/channel/UndoBar.tsx

@@ -0,0 +1,12 @@
+import { Button } from '@/ui/Button';
+import styles from './UndoBar.module.css';
+
+/** 删除后 5 秒内可撤销(ui-design §8) */
+export function UndoBar({ onUndo }: { onUndo: () => void }) {
+  return (
+    <div className={styles.bar} role="status">
+      <span>已删除</span>
+      <Button variant="ghost" icon="undo" onClick={onUndo}>撤销</Button>
+    </div>
+  );
+}