feat(api): add chat configuration and conversation message list APIs; update types and integrate into index

src/components/chat/ChatHistoryPanel.tsx

@@ -45,8 +45,6 @@ function ChatHistoryPanel({
   const [menuState, setMenuState] = useState<MenuState>(null);
   const [isCompact, setIsCompact] = useState(false);
 
-  const hasSessions = buckets.some((bucket) => bucket.sessions.length > 0);
-
   useEffect(() => {
     setCollapsedBuckets((current) => {
       const next: Record<string, boolean> = {};
@@ -164,12 +162,6 @@ function ChatHistoryPanel({
             </div>
           ) : null}
 
-          {!loading && !hasSessions ? (
-            <div className="rounded-[18px] border border-dashed border-[#dbe7f4] bg-white px-4 py-8 text-sm text-[#94a3b8] shadow-[0_4px_14px_rgba(15,23,42,0.04)] dark:border-[#2a2a2d] dark:bg-[#202024] dark:text-gray-400">
-              还没有对话，点击“新对话”开始。
-            </div>
-          ) : null}
-
           {!isCompact
             ? buckets.map((bucket) => {
                 const isCollapsed = collapsedBuckets[bucket.key] ?? false;