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

claude-hooks-config.example.json

@@ -0,0 +1,32 @@
+{
+  "hooks": {
+    "after_code_edit": {
+      "command": "code",
+      "args": [
+        "--command",
+        "aiDiffPreview.handleHook",
+        "--type",
+        "after_code_edit",
+        "--file",
+        "${file}",
+        "--patch",
+        "${patch}"
+      ],
+      "description": "AI 代码编辑后触发 Diff 预览"
+    },
+    "after_write_file": {
+      "command": "code",
+      "args": [
+        "--command",
+        "aiDiffPreview.handleHook",
+        "--type",
+        "after_write_file",
+        "--file",
+        "${file}",
+        "--patch",
+        "${patch}"
+      ],
+      "description": "文件写入后触发 Diff 预览"
+    }
+  }
+}