feat(shared,tests): add error boundaries, lib utils, i18n messages, and integration tests

shared:

- Add class-filter, error-state, route-error, section-error-boundary, widget-boundary components

- Add ui/alert component

- Add constants directory

- Add breached-password, export-utils, permission-bitmap, rate-limit, resolve-action-error, route-permissions, route-resolver, type-guards lib

- Add i18n messages (en, zh-CN) for invitation-codes, parent, questions, rbac

tests:

- Add integration tests for elective

- Add tests/setup/empty-stub

scripts:

- Add update-md.cjs, tmp_append_en.ps1, tmp_merge_en.ps1 utilities

tests/e2e/smoke-auth.spec.ts

@@ -12,9 +12,12 @@ test.describe("auth smoke", () => {
   test("register page renders required controls", async ({ page }) => {
     await page.goto("/register")
     await expect(page).toHaveTitle(/Register/i)
-    await expect(page.getByLabel("Full Name")).toBeVisible()
-    await expect(page.getByLabel("Email")).toBeVisible()
-    await expect(page.getByLabel("Password")).toBeVisible()
-    await expect(page.getByRole("button", { name: "Create Account" })).toBeVisible()
+    // 注册表单当前使用中文文案；P1 i18n 阶段会切换为 next-intl 翻译键，
+    // 届时此处的选择器应改用 data-testid 或 i18n 键以确保语言无关。
+    await expect(page.getByLabel("姓名")).toBeVisible()
+    await expect(page.getByLabel("邮箱")).toBeVisible()
+    await expect(page.getByLabel("密码")).toBeVisible()
+    await expect(page.getByRole("button", { name: "创建账户" })).toBeVisible()
   })
 })
+