feat: 初始化 AI Code Diff Preview 插件项目

- 核心架构搭建：四层架构设计（触发层、隔离层、Diff引擎、UI层）
- 快照管理器：管理 Base/Suggest 双版本，隔离 AI 生成代码
- Diff 引擎：基于 Myers 算法计算差异，生成变更块
- 内联装饰器：红绿高亮显示删除/新增行
- CodeLens 提供器：提供 Accept/Reject 按钮
- 事务处理：Accept/Reject 原子化操作
- Claude Hooks 集成：支持 after_code_edit/after_write_file 事件
- 状态栏显示：实时显示变更状态
- 基础测试用例：7 个测试全部通过

技术栈：TypeScript + VSCode Extension API + diff 库 + esbuild

src/render/codeLensProvider.ts

@@ -0,0 +1,96 @@
+/**
+ * CodeLens 提供器 - 提供 Accept/Reject 按钮
+ */
+
+import * as vscode from 'vscode';
+import { SnapshotManager } from '../snapshot/snapshotManager';
+import { COMMANDS } from '../models/constants';
+
+export class CodeLensProvider implements vscode.CodeLensProvider {
+  private _onDidChangeCodeLenses = new vscode.EventEmitter<void>();
+  readonly onDidChangeCodeLenses = this._onDidChangeCodeLenses.event;
+
+  constructor(private snapshotManager: SnapshotManager) {}
+
+  /**
+   * 刷新 CodeLens
+   */
+  refresh(): void {
+    this._onDidChangeCodeLenses.fire();
+  }
+
+  /**
+   * 提供 CodeLens
+   */
+  provideCodeLenses(
+    document: vscode.TextDocument,
+    token: vscode.CancellationToken
+  ): vscode.CodeLens[] {
+    const snapshot = this.snapshotManager.getSnapshotByFilePath(document.uri.fsPath);
+    if (!snapshot || snapshot.status !== 'active') {
+      return [];
+    }
+
+    const codeLenses: vscode.CodeLens[] = [];
+
+    // 为每个待处理的块添加 CodeLens
+    snapshot.chunks.forEach(chunk => {
+      if (chunk.status !== 'pending') return;
+
+      const range = new vscode.Range(
+        new vscode.Position(chunk.startLine, 0),
+        new vscode.Position(chunk.startLine, 0)
+      );
+
+      // Accept 按钮
+      codeLenses.push(
+        new vscode.CodeLens(range, {
+          title: '$(check) Accept',
+          command: COMMANDS.ACCEPT_CHUNK,
+          arguments: [snapshot.id, chunk.id],
+          tooltip: '接受此变更块',
+        })
+      );
+
+      // Reject 按钮
+      codeLenses.push(
+        new vscode.CodeLens(range, {
+          title: '$(close) Reject',
+          command: COMMANDS.REJECT_CHUNK,
+          arguments: [snapshot.id, chunk.id],
+          tooltip: '拒绝此变更块',
+        })
+      );
+    });
+
+    // 如果有多个块，添加全局操作按钮
+    const pendingChunks = snapshot.chunks.filter(c => c.status === 'pending');
+    if (pendingChunks.length > 1) {
+      const firstChunk = pendingChunks[0];
+      const range = new vscode.Range(
+        new vscode.Position(firstChunk.startLine, 0),
+        new vscode.Position(firstChunk.startLine, 0)
+      );
+
+      codeLenses.push(
+        new vscode.CodeLens(range, {
+          title: '$(check-all) Accept All',
+          command: COMMANDS.ACCEPT_ALL,
+          arguments: [snapshot.id],
+          tooltip: '接受所有变更',
+        })
+      );
+
+      codeLenses.push(
+        new vscode.CodeLens(range, {
+          title: '$(trash) Reject All',
+          command: COMMANDS.REJECT_ALL,
+          arguments: [snapshot.id],
+          tooltip: '拒绝所有变更',
+        })
+      );
+    }
+
+    return codeLenses;
+  }
+}