feat(frontend): Phase 2/3 hardening release

Roadmap P0
- Ship /logo.svg fallback and rewire asset references (superseded later by
  the project-manager PNG in a separate commit).

Roadmap P1
- Response envelope alignment ({items,total,page,size}) across services
  and query hooks.
- Approval/ticket UX updates tied to the new backend rollback semantics.

Roadmap P2
- React.lazy + Vite manualChunks to split vendor-radix/charts/icons/forms
  from the main bundle and cut initial JS.
- Fix the 181 tsc errors (PaginationParams class + per-service generics).
- Auto-refresh flow for JWT refresh tokens wired into api-client.ts.

Roadmap P3
- i18n: i18next + language detector, en/ar locales, RTL auto-switch,
  LanguageToggle component in RoleLayout and AdminLmsLayout.
- GDPR: PrivacyCenter page for data export and right-to-erasure, backed
  by gdpr.service.ts; logout via AuthContext after erasure.
- Human-in-the-loop exam review UI: admin ExamReviewQueue + ExamReviewDetail
  pages, useExamReview hooks, exam-review.service.ts.
- AI quality loop: AIPromptEditor (versioning + render preview),
  AIFeedbackButtons for students, AIFeedbackTriage admin page, dedicated
  services, hooks, and types.
- Dark mode: ThemeProvider + ThemeToggle + chart color tokens.
- Accessibility: DialogDescription on every DialogContent; alert-dialog
  and sheet updates.
- Retire dead pages: ExamPage marketing, Index, ProfilePage import.
- Playwright e2e scaffolding: playwright.config.ts + e2e/login.spec.ts
  smoke tests, npm scripts test:e2e / test:e2e:install.

Made-with: Cursor

frontend/src/i18n/index.ts

@@ -0,0 +1,67 @@
+/**
+ * EnCoach i18n bootstrap.
+ *
+ * We keep the translation strings in TypeScript modules (one per locale) so
+ * they go through type-checking and tree-shaking, and so non-translators
+ * can't ship a broken JSON file that blocks the build.
+ *
+ * Language detection order:
+ *   1. localStorage key ``encoach-lang`` (explicit user pick)
+ *   2. ``navigator.language``
+ *   3. fallback ``en``
+ *
+ * RTL handling: whenever the active language switches to one of RTL_LANGS,
+ * we flip ``document.documentElement.dir`` so Tailwind's RTL utilities +
+ * Radix primitives pick up the change automatically.
+ */
+
+import i18n from "i18next";
+import LanguageDetector from "i18next-browser-languagedetector";
+import { initReactI18next } from "react-i18next";
+
+import ar from "./locales/ar";
+import en from "./locales/en";
+
+const RTL_LANGS = new Set(["ar", "he", "fa", "ur"]);
+
+export const SUPPORTED_LANGS = [
+  { code: "en", label: "English" },
+  { code: "ar", label: "العربية" },
+] as const;
+
+export type SupportedLang = (typeof SUPPORTED_LANGS)[number]["code"];
+
+i18n
+  .use(LanguageDetector)
+  .use(initReactI18next)
+  .init({
+    resources: {
+      en: { translation: en },
+      ar: { translation: ar },
+    },
+    fallbackLng: "en",
+    supportedLngs: SUPPORTED_LANGS.map((l) => l.code),
+    interpolation: { escapeValue: false },
+    detection: {
+      order: ["localStorage", "navigator", "htmlTag"],
+      caches: ["localStorage"],
+      lookupLocalStorage: "encoach-lang",
+    },
+    returnEmptyString: false,
+  });
+
+export function applyDirectionForLang(lang: string) {
+  const base = lang.split("-")[0];
+  const dir = RTL_LANGS.has(base) ? "rtl" : "ltr";
+  if (typeof document !== "undefined") {
+    document.documentElement.dir = dir;
+    document.documentElement.lang = base;
+  }
+}
+
+if (typeof window !== "undefined") {
+  applyDirectionForLang(i18n.language || "en");
+  i18n.on("languageChanged", applyDirectionForLang);
+}
+
+export default i18n;