Updated PLANS.md, AGENTS.md, and arabic-localization.md to reflect the “foundations now, full translations later” approach and marked progress accordingly.

Implemented localization foundations across backend and frontend (locale settings/middleware, preferred language, i18n wiring, RTL support, minimal Arabic UI strings, Accept-Language).
Added targeted backend and frontend tests plus a risks note for pending full translation coverage.

frontend/src/App.test.jsx

@@ -1,12 +1,23 @@
-import { render, screen } from "@testing-library/react";
+import { fireEvent, render, screen, waitFor } from "@testing-library/react";
 import App from "./App.jsx";
-
+import i18n from "./i18n";
 
 describe("App", () => {
-  it("renders the hero copy", () => {
+  it("renders the hero copy", async () => {
+    await i18n.changeLanguage("en");
     render(<App />);
     expect(
       screen.getByText("Find, compare, and book top salons near you.")
     ).toBeInTheDocument();
   });
+
+  it("switches to Arabic and sets RTL direction", async () => {
+    await i18n.changeLanguage("en");
+    render(<App />);
+    fireEvent.click(screen.getByRole("button", { name: "العربية" }));
+    await waitFor(() => {
+      expect(document.documentElement.dir).toBe("rtl");
+    });
+    expect(screen.getByText("الصالونات")).toBeInTheDocument();
+  });
 });