chore: add comprehensive documentation and testing infrastructure

## 文档（全部中文）
- AGENTS.md - 完整的 AI 编码指南（中文版）
- CONTRIBUTING.md - 贡献指南
- DEVELOPMENT.md - 开发文档
- DEPLOYMENT.md - 部署文档
- TESTING.md - 测试文档
- TROUBLESHOOTING.md - 问题排查指南
- FAQ.md - 常见问题
- WORKFLOW.md - 标准开发流程文档
## AI 工作流（9个详细工作流）
- feature-development.md - 新功能开发流程
- bug-fix.md - Bug 修复流程
- code-review.md - 代码审查流程
- testing.md - 测试编写流程
- release.md - 发布流程
- refactoring.md - 代码重构流程
- documentation.md - 文档更新流程
- performance-optimization.md - 性能优化流程
- security-audit.md - 安全审计流程
## 测试基础设施
- vitest.config.ts - Vitest 单元测试配置
- playwright.config.ts - Playwright E2E 测试配置
- src/__tests__/setup.ts - 测试环境设置
- src/__tests__/unit/downloadStatus.test.ts - 示例单元测试
- e2e/basic.spec.ts - 示例 E2E 测试
## CI/CD
- .github/workflows/test.yml - 新建测试 CI 工作流
- .github/workflows/build.yml - 更新构建工作流，添加测试步骤
## Issue 模板
- 更新 bug_report.md 为标准 Bug 报告模板
- 更新 help_wanted.md 为标准功能请求模板
## 配置更新
- package.json - 添加测试依赖和 7 个新的 npm 脚本
- .gitignore - 添加测试相关忽略项
## 新增 npm 脚本
- test - 运行单元测试
- test:watch - 监听模式
- test:coverage - 生成覆盖率报告
- test:e2e - 运行 E2E 测试
- test:e2e:ui - E2E UI 模式
- test:e2e:debug - E2E 调试模式
- test:all - 运行所有测试
## 新增测试依赖
- @playwright/test ^1.40.0
- @testing-library/jest-dom ^6.1.5
- @testing-library/vue ^8.0.1
- @vitest/coverage-v8 ^1.0.0
- @vue/test-utils ^2.4.3
- jsdom ^23.0.1
- vitest ^1.0.0

src/__tests__/setup.ts

@@ -0,0 +1,30 @@
+import { expect, afterEach, vi } from "vitest";
+import { cleanup } from "@testing-library/vue";
+import * as matchers from "@testing-library/jest-dom/matchers";
+
+// 扩展 Vitest 的 expect
+expect.extend(matchers);
+
+// 每个测试后清理
+afterEach(() => {
+  cleanup();
+});
+
+// Mock window.ipcRenderer
+global.window = Object.create(window);
+Object.defineProperty(window, "ipcRenderer", {
+  value: {
+    send: vi.fn(),
+    on: vi.fn(),
+    off: vi.fn(),
+    invoke: vi.fn(),
+    removeListener: vi.fn(),
+  },
+});
+
+// Mock window.apm_store
+Object.defineProperty(window, "apm_store", {
+  value: {
+    arch: "amd64-store",
+  },
+});

src/__tests__/unit/downloadStatus.test.ts

@@ -0,0 +1,67 @@
+import { describe, it, expect, beforeEach } from "vitest";
+import {
+  downloads,
+  addDownload,
+  removeDownloadItem,
+} from "@/global/downloadStatus";
+import type { DownloadItem } from "@/global/typedefinition";
+
+describe("downloadStatus", () => {
+  beforeEach(() => {
+    downloads.value = [];
+  });
+
+  describe("addDownload", () => {
+    it("should add a new download item", () => {
+      const mockDownload: DownloadItem = {
+        id: 1,
+        name: "Test App",
+        pkgname: "test-app",
+        version: "1.0.0",
+        icon: "",
+        status: "queued",
+        progress: 0,
+        downloadedSize: 0,
+        totalSize: 1000000,
+        speed: 0,
+        timeRemaining: 0,
+        startTime: Date.now(),
+        logs: [],
+        source: "Test",
+        retry: false,
+      };
+
+      addDownload(mockDownload);
+
+      expect(downloads.value).toHaveLength(1);
+      expect(downloads.value[0].pkgname).toBe("test-app");
+    });
+  });
+
+  describe("removeDownloadItem", () => {
+    it("should remove download by pkgname", () => {
+      const mockDownload: DownloadItem = {
+        id: 1,
+        name: "Test App",
+        pkgname: "test-app",
+        version: "1.0.0",
+        icon: "",
+        status: "queued",
+        progress: 0,
+        downloadedSize: 0,
+        totalSize: 1000000,
+        speed: 0,
+        timeRemaining: 0,
+        startTime: Date.now(),
+        logs: [],
+        source: "Test",
+        retry: false,
+      };
+
+      downloads.value.push(mockDownload);
+      removeDownloadItem("test-app");
+
+      expect(downloads.value).toHaveLength(0);
+    });
+  });
+});