feat: 添加完整的单元测试套件

- 新增 vitest 测试框架配置
- 添加 54 个测试文件，共 951 个测试用例
- 覆盖核心模块：
  - Agent: executor, registry, config-loader, permission-merger
  - Context: manager, compaction, prune, token-counter
  - Permission: manager, bash/file/git/web checkers, wildcard
  - Session: manager, storage
  - Tools: filesystem (12个), git (10个), web, shell, todo, task
  - LSP: client, server, language
  - Utils: config, diff
  - UI: terminal

package.json

@@ -11,7 +11,10 @@
     "build": "tsc && mkdir -p dist/tools/descriptions && cp -r src/tools/descriptions/* dist/tools/descriptions/",
     "start": "node dist/index.js",
     "dev": "tsx src/index.ts",
-    "lint": "eslint src/**/*.ts"
+    "lint": "eslint src/**/*.ts",
+    "test": "vitest run",
+    "test:watch": "vitest",
+    "test:coverage": "vitest run --coverage"
   },
   "keywords": [
     "ai",
@@ -41,7 +44,9 @@
   "devDependencies": {
     "@types/js-yaml": "^4.0.9",
     "@types/node": "^22.0.0",
+    "@vitest/coverage-v8": "^4.0.15",
     "tsx": "^4.19.0",
-    "typescript": "^5.6.0"
+    "typescript": "^5.6.0",
+    "vitest": "^4.0.15"
   }
 }