feat(web): connect quick share flow

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

web/src/features/scan/JoinScreen.tsx

@@ -0,0 +1,38 @@
+import type { ChannelInfo } from '@/core-bridge/types';
+import type { ParsedChannelLink } from '@/lib/channelLink';
+import { useChannels } from '@/store/channels';
+import { Button } from '@/ui/Button';
+import { JoinPreview } from './JoinPreview';
+import styles from './JoinScreen.module.css';
+
+interface Props {
+  link: ParsedChannelLink;
+  onJoined: (c: ChannelInfo) => void;
+  onCancel: () => void;
+}
+
+/** 别人发来的频道链接:整页预览,确认后才加入 */
+export function JoinScreen({ link, onJoined, onCancel }: Props) {
+  const join = useChannels((s) => s.join);
+  return (
+    <div className={styles.page}>
+      <main className={styles.card}>
+        <h1 className={styles.title}>加入频道</h1>
+        <JoinPreview link={link} onJoin={join} onJoined={onJoined} onBack={onCancel} backLabel="取消" />
+      </main>
+    </div>
+  );
+}
+
+/** 路由里有频道 id,但本机没有这个频道,链接里也没有密钥(例如刷新后 fragment 已被清除) */
+export function MissingAccess({ onHome }: { onHome: () => void }) {
+  return (
+    <div className={styles.page}>
+      <main className={styles.card}>
+        <h1 className={styles.title}>无法打开此频道</h1>
+        <p className={styles.dim}>本机没有这个频道的链接。请使用完整的分享链接(含 # 后面的密钥)重新打开,或扫描对方的二维码。</p>
+        <Button variant="primary" onClick={onHome}>回到首页</Button>
+      </main>
+    </div>
+  );
+}