feat(desktop): simple mode UI — ChatArea compact + SimpleSidebar + RightPanel dual-mode

Adapt ChatArea for compact/butler mode:
- Add onOpenDetail prop for expanding to full view
- Remove inline export dialog (moved to detail view)
- Replace SquarePen with ClipboardList icon

Add SimpleSidebar component for butler simple mode:
- Two tabs: 对话 / 行业资讯
- Quick suggestion buttons
- Minimal navigation

RightPanel refactoring for dual-mode support:
- Detect simple vs professional mode
- Conditional rendering based on butler mode state

desktop/src/components/ChatArea.tsx

@@ -10,7 +10,7 @@ import { useConfigStore } from '../store/configStore';
 import { useSaaSStore } from '../store/saasStore';
 import { type UnlistenFn } from '@tauri-apps/api/event';
 import { safeListenEvent } from '../lib/safe-tauri';
-import { Paperclip, SquarePen, ArrowUp, MessageSquare, Download, X, FileText, Image as ImageIcon, Search } from 'lucide-react';
+import { Paperclip, ArrowUp, MessageSquare, Download, X, FileText, Image as ImageIcon, Search, ClipboardList } from 'lucide-react';
 import { Button, EmptyState, MessageListSkeleton, LoadingDots } from './ui';
 import { ResizableChatLayout } from './ai/ResizableChatLayout';
 import { ArtifactPanel } from './ai/ArtifactPanel';
@@ -49,11 +49,11 @@ const DEFAULT_MESSAGE_HEIGHTS: Record<string, number> = {
 // Threshold for enabling virtualization (messages count)
 const VIRTUALIZATION_THRESHOLD = 100;
 
-export function ChatArea({ compact }: { compact?: boolean }) {
+export function ChatArea({ compact, onOpenDetail }: { compact?: boolean; onOpenDetail?: () => void }) {
   const {
     messages, isStreaming, isLoading,
     sendMessage: sendToGateway, initStreamListener,
-    newConversation, chatMode, setChatMode, suggestions,
+    chatMode, setChatMode, suggestions,
     totalInputTokens, totalOutputTokens,
   } = useChatStore();
   const currentAgent = useConversationStore((s) => s.currentAgent);
@@ -239,23 +239,6 @@ export function ChatArea({ compact }: { compact?: boolean }) {
 
   const connected = connectionState === 'connected';
 
-  // Export current conversation as Markdown
-  const exportCurrentConversation = () => {
-    const title = currentAgent?.name || 'ZCLAW 对话';
-    const lines = [`# ${title}`, '', `导出时间: ${new Date().toLocaleString('zh-CN')}`, ''];
-    for (const msg of messages) {
-      const label = msg.role === 'user' ? '用户' : msg.role === 'assistant' ? '助手' : msg.role;
-      lines.push(`## ${label}`, '', msg.content, '');
-    }
-    const blob = new Blob([lines.join('\n')], { type: 'text/markdown;charset=utf-8' });
-    const url = URL.createObjectURL(blob);
-    const a = document.createElement('a');
-    a.href = url;
-    a.download = `${title.replace(/[/\\?%*:|"<>]/g, '_')}.md`;
-    a.click();
-    URL.revokeObjectURL(url);
-  };
-
   // Build artifact panel content
   const artifactRightPanel = (
     <ArtifactPanel
@@ -364,28 +347,16 @@ export function ChatArea({ compact }: { compact?: boolean }) {
               <Search className="w-3.5 h-3.5" />
             </Button>
           )}
-          {messages.length > 0 && (
+          {/* 详情按钮 (简洁模式) */}
+          {compact && onOpenDetail && (
             <Button
               variant="ghost"
               size="sm"
-              onClick={exportCurrentConversation}
-              className="flex items-center gap-2 text-gray-600 dark:text-gray-400 hover:bg-gray-50 dark:hover:bg-gray-800 rounded-lg transition-colors"
-              title="导出对话"
+              onClick={onOpenDetail}
+              className="flex items-center gap-1 text-gray-600 dark:text-gray-400 hover:bg-gray-50 dark:hover:bg-gray-800 rounded-lg transition-colors"
+              title="详情"
             >
-              <Download className="w-3.5 h-3.5" />
-              <span className="text-sm">导出</span>
-            </Button>
-          )}
-          {messages.length > 0 && (
-            <Button
-              variant="ghost"
-              size="sm"
-              onClick={newConversation}
-              className="flex items-center gap-2 text-gray-600 dark:text-gray-400 hover:bg-gray-50 dark:hover:bg-gray-800 rounded-lg transition-colors"
-              title="新对话"
-            >
-              <SquarePen className="w-3.5 h-3.5" />
-              新对话
+              <ClipboardList className="w-3.5 h-3.5" />
             </Button>
           )}
         </div>