feat(web): bulk forward/favorite in multi-select mode

Rounds out the multi-select bottom bar (README §3.6) with 转发/收藏 alongside
the existing 删除 -- reuses the single-message ForwardPickerModal/
favoriteMessages/forwardMessage machinery from the context-menu actions,
just applied to the whole selected set. One "转发" button (not separate
逐条/合并 buttons) matching the old app's real dialog-internal mode toggle,
which this app's simplified single-target picker doesn't model -- already
noted as a scope cut in ForwardPickerModal's own docstring.

Verified live: entering multi-select via a message's context menu shows
转发/收藏/删除, and bulk-favorite POSTs a real /v1/im/favorites/batch request.

Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com>

web/src/features/messages/ConversationView.tsx

@@ -47,6 +47,7 @@ export function ConversationView() {
   const [selectedSeqs, setSelectedSeqs] = useState<Set<number>>(new Set());
   const [loadingOlder, setLoadingOlder] = useState(false);
   const [recording, setRecording] = useState(false);
+  const [bulkForwardOpen, setBulkForwardOpen] = useState(false);
   const [replyTo, setReplyTo] = useState<StoredMessage | null>(null);
   const [forwardMsg, setForwardMsg] = useState<StoredMessage | null>(null);
   const [emojiOpen, setEmojiOpen] = useState(false);
@@ -161,6 +162,22 @@ export function ConversationView() {
     exitSelectMode();
   };
 
+  const bulkFavorite = () => {
+    if (selectedSeqs.size === 0) return;
+    favoriteMessages([...selectedSeqs].map((seq) => ({ topic: topicId, seq }))).catch(() => {});
+    exitSelectMode();
+  };
+
+  const bulkForward = (targetTopic: string) => {
+    const target = tinode.getTopic(targetTopic);
+    for (const seq of selectedSeqs) {
+      const msg = topic.findMessage(seq);
+      if (msg) forwardMessage(topicId, msg, target);
+    }
+    setBulkForwardOpen(false);
+    exitSelectMode();
+  };
+
   const handleAction = (action: MessageAction) => {
     const msg = menu?.msg;
     setMenu(null);
@@ -275,6 +292,24 @@ export function ConversationView() {
 
       {selectMode ? (
         <div className="flex h-18 flex-none items-center justify-around border-t border-border-panel bg-white">
+          <button
+            type="button"
+            onClick={() => setBulkForwardOpen(true)}
+            disabled={selectedSeqs.size === 0}
+            className="flex flex-col items-center gap-1 text-text-secondary disabled:opacity-40"
+          >
+            <Icon name="reply" className="text-[22px]" />
+            <span className="text-xs">转发</span>
+          </button>
+          <button
+            type="button"
+            onClick={bulkFavorite}
+            disabled={selectedSeqs.size === 0}
+            className="flex flex-col items-center gap-1 text-text-secondary disabled:opacity-40"
+          >
+            <Icon name="inventory_2" className="text-[22px]" />
+            <span className="text-xs">收藏</span>
+          </button>
           <button type="button" onClick={bulkDelete} className="flex flex-col items-center gap-1 text-danger-text">
             <Icon name="delete_outline" className="text-[22px]" />
             <span className="text-xs">删除</span>
@@ -379,6 +414,8 @@ export function ConversationView() {
           }}
         />
       ) : null}
+
+      {bulkForwardOpen ? <ForwardPickerModal onClose={() => setBulkForwardOpen(false)} onPick={bulkForward} /> : null}
     </div>
   );
 }