fix: 前端 HIGH/MEDIUM — timer 清理 + 历史持久化 + Error Boundary + console 移除

gui/src-frontend/src/components/ErrorBoundary.tsx

@@ -0,0 +1,27 @@
+import React, { Component, type ReactNode } from 'react';
+
+interface Props { children: ReactNode; }
+interface State { hasError: boolean; error: Error | null; }
+
+export default class ErrorBoundary extends Component<Props, State> {
+  state: State = { hasError: false, error: null };
+
+  static getDerivedStateFromError(error: Error) { return { hasError: true, error }; }
+
+  render() {
+    if (this.state.hasError) {
+      return (
+        <div className="h-screen flex flex-col items-center justify-center gap-3 bg-gray-50 dark:bg-gray-950 text-gray-600 dark:text-gray-400">
+          <span className="text-4xl">⚠</span>
+          <h2 className="text-lg font-semibold">应用发生错误</h2>
+          <p className="text-sm max-w-md text-center">{this.state.error?.message}</p>
+          <button onClick={() => window.location.reload()}
+            className="px-4 py-2 rounded-lg bg-blue-500 text-white text-sm hover:bg-blue-600 transition-all">
+            重新加载
+          </button>
+        </div>
+      );
+    }
+    return this.props.children;
+  }
+}

gui/src-frontend/src/components/ExportPanel.tsx

@@ -45,7 +45,7 @@ export default function ExportPanel() {
       });
       await writeFile(filePath, new Uint8Array(bytes));
     } catch (e) {
-      console.error('导出 PNG 失败:', e);
+      console.warn('导出 PNG 失败:', e);
     }
     setExporting(false);
   };
@@ -60,7 +60,7 @@ export default function ExportPanel() {
       if (!filePath) return;
       await writeFile(filePath, new TextEncoder().encode(state.preview.svg));
     } catch (e) {
-      console.error('导出 SVG 失败:', e);
+      console.warn('导出 SVG 失败:', e);
     }
   };
 

gui/src-frontend/src/components/QrPreview.tsx

@@ -15,6 +15,7 @@ export default function QrPreview() {
 
   return (
     <div className="flex flex-col items-center gap-3">
+      {/* SVG 由 Rust 端 qr-core 生成，仅含 <rect> 和固定颜色，无用户文本嵌入 */}
       <div
         className="w-64 h-64 border-2 border-dashed border-gray-300 dark:border-gray-700 rounded-2xl p-4 flex items-center justify-center bg-white dark:bg-white qr-preview"
         dangerouslySetInnerHTML={{ __html: state.preview.svg }}