fix(butler): wire verification gaps — pain storage init, cold start, UI mode switches

- Call init_pain_storage() in Tauri .setup() so pain persistence activates on boot
- Integrate useColdStart hook into FirstConversationPrompt for auto-greeting
- Add UI mode toggle section to Settings/General (already had imports)
- Add "简洁" mode switch-back button to TopBar in professional layout
- Update SemanticSkillRouter @reserved annotation to reflect active status

desktop/src/components/Settings/General.tsx

@@ -3,6 +3,7 @@ import { useConnectionStore } from '../../store/connectionStore';
 import { useConfigStore } from '../../store/configStore';
 import { useConversationStore } from '../../store/chat/conversationStore';
 import { useSaaSStore } from '../../store/saasStore';
+import { useUIModeStore } from '../../store/uiModeStore';
 import { getStoredGatewayToken, setStoredGatewayToken } from '../../lib/gateway-client';
 import { silentErrorHandler } from '../../lib/error-utils';
 
@@ -20,6 +21,8 @@ export function General() {
   const [showToolCalls, setShowToolCalls] = useState(quickConfig.showToolCalls ?? false);
   const [gatewayToken, setGatewayToken] = useState(getStoredGatewayToken());
   const [isSaving, setIsSaving] = useState(false);
+  const mode = useUIModeStore((s) => s.mode);
+  const setMode = useUIModeStore((s) => s.setMode);
 
   const connected = connectionState === 'connected';
   const connecting = connectionState === 'connecting' || connectionState === 'reconnecting';
@@ -185,6 +188,35 @@ export function General() {
           </div>
           <Toggle checked={showToolCalls} onChange={handleShowToolCallsChange} disabled={isSaving} />
         </div>
+
+        <div>
+          <div className="text-sm font-medium text-gray-900">界面模式</div>
+          <div className="text-xs text-gray-500 mt-0.5 mb-2">切换简洁界面或完整专业界面。</div>
+          <div className="flex gap-3">
+            <button
+              onClick={() => setMode('simple')}
+              className={`flex-1 p-3 rounded-lg border text-sm text-center transition-colors ${
+                mode === 'simple'
+                  ? 'border-orange-500 bg-orange-50 text-orange-700 dark:bg-orange-900/20 dark:text-orange-300'
+                  : 'border-gray-200 hover:bg-gray-50 dark:border-gray-700 dark:hover:bg-gray-800'
+              }`}
+            >
+              简洁模式
+              <p className="text-xs text-gray-500 mt-1">适合日常使用，只显示聊天窗口</p>
+            </button>
+            <button
+              onClick={() => setMode('professional')}
+              className={`flex-1 p-3 rounded-lg border text-sm text-center transition-colors ${
+                mode === 'professional'
+                  ? 'border-orange-500 bg-orange-50 text-orange-700 dark:bg-orange-900/20 dark:text-orange-300'
+                  : 'border-gray-200 hover:bg-gray-50 dark:border-gray-700 dark:hover:bg-gray-800'
+              }`}
+            >
+              专业模式
+              <p className="text-xs text-gray-500 mt-1">完整功能，包括侧边栏和工具面板</p>
+            </button>
+          </div>
+        </div>
       </div>
     </div>
   );