refactor: RBAC权限系统重构 + UI组件拆分 + 测试修复 + 架构文档

- RBAC: 新增30个权限点、DataScope行级权限、requirePermission守卫，所有57+ Server Action接入权限校验
- UI拆分: exam-form(1623行→11文件)、textbook-reader(744行→7文件)，均降至300行以内
- 测试: 新增5个单元测试文件(19用例)，修复4个集成测试文件(38用例全部通过)
- 架构文档: 新增架构影响地图(004/005)、标准功能清单(006)、差距审计报告(007)
- 项目规则: 架构图优先规则，改码必同步图
- 安全: rehype-sanitize净化、AES加密API Key、权限路由守卫
- 无障碍: skip-link、aria-label、prefers-reduced-motion
- 性能: next/font优化、next/image、代码分割

src/shared/hooks/use-local-storage.test.ts

@@ -0,0 +1,35 @@
+import { describe, it, expect, beforeEach } from "vitest"
+import { renderHook, act } from "@testing-library/react"
+import { useLocalStorage } from "./use-local-storage"
+
+describe("useLocalStorage", () => {
+  beforeEach(() => {
+    localStorage.clear()
+  })
+
+  it("should return initial value when localStorage is empty", () => {
+    const { result } = renderHook(() => useLocalStorage("test-key", "default"))
+    expect(result.current[0]).toBe("default")
+  })
+
+  it("should persist value to localStorage", () => {
+    const { result } = renderHook(() => useLocalStorage("test-key", "default"))
+
+    act(() => {
+      result.current[1]("updated")
+    })
+
+    expect(result.current[0]).toBe("updated")
+    expect(localStorage.getItem("test-key")).toBe(JSON.stringify("updated"))
+  })
+
+  it("should support functional updates", () => {
+    const { result } = renderHook(() => useLocalStorage("test-key", 0))
+
+    act(() => {
+      result.current[1]((prev) => prev + 1)
+    })
+
+    expect(result.current[0]).toBe(1)
+  })
+})