优化代码显示组件的变量值展示

1. 增强变量监视面板：
   - 按类型分组显示变量（节点、值、结果、其他）
   - 添加步骤类型标签显示当前执行阶段
   - 为不同类型变量添加颜色编码和图标

2. 改进代码行内变量标注：
   - 根据步骤类型智能选择显示的变量
   - 添加高亮脉冲动画效果
   - 为布尔值添加图标（✓/✗）

3. 优化样式：
   - 增强debug效果的视觉呈现
   - 改进变量标签的悬停效果
   - 优化响应式布局

4. 修复编译错误：
   - 导出预留功能函数
   - 清理未使用的导入和变量

Author: CC11001100

.kiro/specs/algorithm-visualization-platform/design.md

@@ -0,0 +1,367 @@
+# Design Document: Algorithm Visualization Platform
+
+## Overview
+
+本设计文档描述一个以教学为目的的 LeetCode 算法可视化演示平台。平台使用 TypeScript + React + D3.js 技术栈，以单屏幕形式展示算法的分步骤执行过程。核心目标是通过交互式画布、代码同步高亮、数据流可视化等功能，帮助用户直观理解算法执行过程。
+
+## Architecture
+
+### 整体架构
+
+```
+┌─────────────────────────────────────────────────────────────────┐
+│                         Header                                   │
+│  [GitHub ⭐] [101. 对称二叉树 →]                                 │
+├─────────────────────────────────────────────────────────────────┤
+│  [输入框] [样例1] [样例2] [样例3] [🎲随机]                        │
+├─────────────────────────────────────────────────────────────────┤
+│                                                                 │
+│  ┌─────────────────────────────┐  ┌──────────────────────────┐  │
+│  │                             │  │  Code Display            │  │
+│  │      Canvas (D3.js)         │  │  ┌────────────────────┐  │  │
+│  │                             │  │  │ Java Python Go JS  │  │  │
+│  │   [Tree Visualization]      │  │  ├────────────────────┤  │  │
+│  │   [Data Flow Arrows]        │  │  │ 1│ public boolean  │  │  │
+│  │   [Annotations]             │  │  │►2│   if (root ==   │  │  │
+│  │   [Recursion Stack]         │  │  │ 3│   return isMir  │  │  │
+│  │                             │  │  │  │     left=1 ✓    │  │  │
+│  │                             │  │  └────────────────────┘  │  │
+│  └─────────────────────────────┘  └──────────────────────────┘  │
+│                                                                 │
+├─────────────────────────────────────────────────────────────────┤
+│  [⏮ R] [⏪ ←] [▶ 空格] [→ ⏩] [⏭]  速度: [0.5x][1x][2x][4x]     │
+│  ████████████░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░  │
+└─────────────────────────────────────────────────────────────────┘
+                                                    [💬 交流群]
+```
+
+### 组件层次结构
+
+```
+App
+├── Header
+│   ├── GitHubBadge (Star count with IndexedDB cache)
+│   └── LeetCodeTitle (Clickable link)
+├── DataInputBar
+│   ├── TextInput
+│   ├── PresetExamples
+│   └── RandomGenerator
+├── MainContent
+│   ├── CanvasPanel
+│   │   ├── TreeVisualization (D3.js)
+│   │   ├── DataFlowArrows
+│   │   ├── AnnotationSystem
+│   │   └── RecursionStackOverlay
+│   └── CodePanel
+│       ├── LanguageTabs
+│       ├── CodeLines (with line numbers)
+│       ├── ExecutionHighlight
+│       └── VariableWatch
+├── BottomControlBar
+│   ├── PlaybackControls
+│   ├── SpeedSelector
+│   └── ProgressBar
+└── WeChatFloat
+```
+
+## Components and Interfaces
+
+### 1. Header 组件
+
+```typescript
+interface HeaderProps {
+  title: string;           // "101. 对称二叉树"
+  leetcodeUrl: string;     // LeetCode 题目链接
+  githubUrl: string;       // GitHub 仓库链接
+  githubRepo: string;      // "owner/repo" 格式
+}
+
+interface GitHubStarCache {
+  stars: number;
+  timestamp: number;       // 缓存时间戳
+}
+```
+
+### 2. DataInputBar 组件
+
+```typescript
+interface DataInputBarProps {
+  onDataChange: (data: TreeData) => void;
+  onError: (error: string) => void;
+}
+
+interface PresetExample {
+  label: string;
+  value: string;
+  description?: string;
+}
+
+// 数据验证函数
+function validateTreeInput(input: string): ValidationResult;
+function generateRandomTree(constraints: TreeConstraints): TreeData;
+```
+
+### 3. CodeDisplay 组件
+
+```typescript
+type Language = 'java' | 'python' | 'golang' | 'javascript';
+
+interface CodeDisplayProps {
+  method: 'recursive' | 'iterative';
+  currentStep: number;
+  variables: VariableMap;
+}
+
+interface CodeLine {
+  lineNumber: number;
+  content: string;
+  isHighlighted: boolean;
+  isExecuting: boolean;
+  variables?: VariableAnnotation[];
+}
+
+interface VariableAnnotation {
+  name: string;
+  value: string | number | boolean | null;
+  type: 'node' | 'value' | 'result' | 'size';
+}
+```
+
+### 4. Canvas 组件
+
+```typescript
+interface CanvasProps {
+  root: TreeNode | null;
+  currentStep: AlgorithmStep;
+  animationEnabled: boolean;
+}
+
+interface DataFlowArrow {
+  from: Position;
+  to: Position;
+  label: string;
+  type: 'value-transfer' | 'comparison' | 'return';
+}
+
+interface Annotation {
+  nodeId: string;
+  text: string;
+  position: 'top' | 'bottom' | 'left' | 'right';
+  type: 'compare' | 'result' | 'info';
+}
+```
+
+### 5. BottomControlBar 组件
+
+```typescript
+interface BottomControlBarProps {
+  currentStep: number;
+  totalSteps: number;
+  isPlaying: boolean;
+  playSpeed: number;
+  onStepChange: (step: number) => void;
+  onPlayToggle: () => void;
+  onSpeedChange: (speed: number) => void;
+  onReset: () => void;
+}
+
+// IndexedDB 存储接口
+interface PlaybackSettings {
+  speed: number;
+  lastUpdated: number;
+}
+```
+
+### 6. WeChatFloat 组件
+
+```typescript
+interface WeChatFloatProps {
+  qrCodeUrl: string;
+  instructions: string;
+}
+```
+
+## Data Models
+
+### TreeNode
+
+```typescript
+interface TreeNode {
+  val: number;
+  left: TreeNode | null;
+  right: TreeNode | null;
+}
+```
+
+### AlgorithmStep
+
+```typescript
+interface AlgorithmStep {
+  stepIndex: number;
+  type: 'initial' | 'compare' | 'check-null' | 'check-value' | 'check-subtree' | 'return' | 'final';
+  message: string;
+  detailedMessage?: string;
+  leftNodeId?: string;
+  rightNodeId?: string;
+  result?: boolean;
+  codeLineNumber: number;
+  variables: VariableMap;
+  annotations: Annotation[];
+  dataFlowArrows: DataFlowArrow[];
+}
+```
+
+### IndexedDB Schema
+
+```typescript
+// Database: leetcode-symmetric-tree-db
+// Stores:
+// 1. github-cache: { key: string, stars: number, timestamp: number }
+// 2. settings: { key: string, value: any }
+```
+
+## Correctness Properties
+
+*A property is a characteristic or behavior that should hold true across all valid executions of a system-essentially, a formal statement about what the system should do. Properties serve as the bridge between human-readable specifications and machine-verifiable correctness guarantees.*
+
+### Property 1: GitHub Star Cache Validity
+*For any* star count fetched from the GitHub API, the system SHALL store it in IndexedDB with a timestamp, and subsequent fetches within one hour SHALL return the cached value without making an API call.
+**Validates: Requirements 2.4**
+
+### Property 2: Random Tree Generation Validity
+*For any* randomly generated tree data, the output SHALL conform to the problem constraints (valid array format, root not null, all values are numbers or null).
+**Validates: Requirements 3.6**
+
+### Property 3: Input Validation Correctness
+*For any* user input string, the validation function SHALL correctly identify whether it represents a valid tree array according to the problem constraints.
+**Validates: Requirements 3.7**
+
+### Property 4: Code-Step Synchronization
+*For any* algorithm step, the code display SHALL highlight the corresponding code line that matches the step's execution point.
+**Validates: Requirements 4.3**
+
+### Property 5: Variable Display Accuracy
+*For any* variable value change during algorithm execution, the displayed value SHALL match the actual value at that step.
+**Validates: Requirements 4.4**
+
+### Property 6: Keyboard Shortcut Consistency
+*For any* keyboard shortcut press (←, →, Space, R), the system SHALL execute the corresponding action (previous step, next step, play/pause, reset).
+**Validates: Requirements 7.5, 7.6, 7.7, 7.8**
+
+### Property 7: Playback Speed Persistence
+*For any* playback speed change, the new speed SHALL be persisted to IndexedDB and restored on page reload.
+**Validates: Requirements 7.10**
+
+### Property 8: No Purple Colors
+*For any* rendered element on the page, its color values SHALL NOT contain purple hues (hue values between 270-330 degrees in HSL color space).
+**Validates: Requirements 10.2**
+
+### Property 9: Comparison Visualization
+*For any* comparison step in the algorithm, the canvas SHALL display visual indicators (arrows, highlights, labels) showing the two values being compared.
+**Validates: Requirements 6.4**
+
+### Property 10: Auto-fit Large Trees
+*For any* tree with more than 7 nodes, the canvas SHALL automatically adjust the zoom level so that all nodes are visible within the viewport.
+**Validates: Requirements 5.4**
+
+## Error Handling
+
+1. **GitHub API 失败**: 使用 IndexedDB 缓存的值，如果无缓存则显示 0
+2. **输入验证失败**: 显示具体错误信息，阻止可视化
+3. **随机生成失败**: 显示错误提示，允许重试
+4. **IndexedDB 不可用**: 降级为内存存储，功能正常但不持久化
+5. **D3.js 渲染错误**: 显示错误边界，提供重置选项
+
+## Testing Strategy
+
+### 单元测试
+
+使用 Vitest 进行单元测试：
+
+1. 测试 `validateTreeInput` 函数正确验证各种输入
+2. 测试 `generateRandomTree` 函数生成有效数据
+3. 测试 `getCodeLineForStep` 函数返回正确的行号
+4. 测试 IndexedDB 缓存读写功能
+5. 测试颜色验证函数排除紫色
+
+### 属性测试
+
+使用 fast-check 进行属性测试：
+
+1. **Property 1 测试**: 生成随机 star 数和时间戳，验证缓存行为
+2. **Property 2 测试**: 多次调用随机生成，验证所有输出都有效
+3. **Property 3 测试**: 生成随机字符串输入，验证验证函数正确分类
+4. **Property 4 测试**: 生成随机步骤序列，验证代码行高亮正确
+5. **Property 5 测试**: 生成随机变量值，验证显示值匹配
+6. **Property 6 测试**: 模拟随机键盘事件，验证动作正确
+7. **Property 7 测试**: 生成随机速度值，验证持久化和恢复
+8. **Property 8 测试**: 检查所有 CSS 颜色值，验证无紫色
+9. **Property 9 测试**: 生成随机比较步骤，验证可视化元素存在
+10. **Property 10 测试**: 生成不同大小的树，验证自动缩放
+
+每个属性测试配置运行至少 100 次迭代。
+
+测试文件命名规范：`*.test.ts`
+
+测试标注格式：
+```typescript
+// **Feature: algorithm-visualization-platform, Property 1: GitHub Star Cache Validity**
+```
+
+## 技术实现细节
+
+### IndexedDB 缓存策略
+
+```typescript
+const CACHE_DURATION = 60 * 60 * 1000; // 1小时
+
+async function getStarCount(repo: string): Promise<number> {
+  const cached = await getCachedStars();
+  if (cached && Date.now() - cached.timestamp < CACHE_DURATION) {
+    return cached.stars;
+  }
+  try {
+    const stars = await fetchFromGitHub(repo);
+    await setCachedStars(stars);
+    return stars;
+  } catch {
+    return cached?.stars ?? 0;
+  }
+}
+```
+
+### 代码-步骤同步映射
+
+```typescript
+// 每种语言、每种方法的步骤类型到代码行的映射
+const stepToLineMap: Record<Language, Record<Method, Record<StepType, number>>> = {
+  java: {
+    recursive: {
+      'initial': 1,
+      'check-null': 6,
+      'check-value': 8,
+      'compare': 9,
+      'check-subtree': 10,
+      'return': 10,
+      'final': 3
+    },
+    // ... 其他方法
+  },
+  // ... 其他语言
+};
+```
+
+### 颜色验证
+
+```typescript
+function isPurple(color: string): boolean {
+  const hsl = colorToHSL(color);
+  return hsl.h >= 270 && hsl.h <= 330;
+}
+
+function validateNoP urple(element: HTMLElement): boolean {
+  const styles = getComputedStyle(element);
+  const colorProps = ['color', 'backgroundColor', 'borderColor', 'fill', 'stroke'];
+  return colorProps.every(prop => !isPurple(styles[prop]));
+}
+```