fix: 发送消息时强制resetAutoScroll，解决手动上滑后新消息不自动滚动的问题

src/renderer/components/chat-area.ts

@@ -102,6 +102,12 @@ export function scrollToBottom(): void {
   });
 }
 
+/** 发送新消息时重置自动滚动，确保新消息可见 */
+export function resetAutoScroll(): void {
+  autoScroll = true;
+  if (scrollBtnEl) scrollBtnEl.style.display = 'none';
+}
+
 export function renderMessages(): void {
   const currentSession = state.get<ChatSession | null>(KEYS.CURRENT_SESSION);
   const msgs = currentSession ? currentSession.messages : [];

src/renderer/components/input-area.ts

@@ -8,7 +8,7 @@ import { detectLanguage, truncate, escapeHtml, formatSize } from '../utils/utils
 import { getSelectedModel, isThinkEnabled, isVisionAvailable, isToolCallingSupported } from './model-bar.js';
 import {
   renderMessages, clearMessagesDOM, appendAssistantPlaceholder, appendSystemMessage,
-  updateLastAssistantMessage, clearMessages, safeMarkdown, enableAutoScroll,
+  updateLastAssistantMessage, clearMessages, safeMarkdown, enableAutoScroll, resetAutoScroll,
   appendToolCallCardToPlaceholder, updateToolCallCardInPlaceholder, resetCurrentPlaceholder
 } from './chat-area.js';
 import { showToast } from './toast.js';
@@ -778,6 +778,7 @@ export async function sendMessage(): Promise<void> {
   }
 
   logInfo(`发送消息: ${model}`, text ? text.slice(0, 60) + (text.length > 60 ? '...' : '') : '[附件消息]');
+  resetAutoScroll(); // 发送新消息时强制恢复自动滚动
 
   if (pendingImages.length > 0 && !isVisionAvailable()) {
     appendSystemMessage('⚠️ 当前模型不支持图片分析，请移除图片后重试');