Add SEO settings and root admin save flows

tests/app-config.test.ts

@@ -0,0 +1,53 @@
+import { describe, expect, it } from "vitest";
+
+import {
+  buildDefaultSiteSettings,
+  parseSiteSettingsValue,
+} from "../lib/site-settings";
+
+describe("site settings helpers", () => {
+  it("builds defaults from the fallback site name", () => {
+    const settings = buildDefaultSiteSettings("Studio Moh");
+
+    expect(settings.locales.ar.siteName).toBe("Studio Moh");
+    expect(settings.locales.ar.titleTemplate).toBe("{pageTitle} | {siteName}");
+    expect(settings.locales.en.siteDescription).toBe("Multilingual Next.js base project");
+    expect(settings.locales.de.subhead).toBe("");
+  });
+
+  it("merges stored values with safe defaults", () => {
+    const settings = parseSiteSettingsValue(
+      JSON.stringify({
+        locales: {
+          en: {
+            siteName: "Brand EN",
+            titleTemplate: "{pageTitle} - {siteName}",
+            siteDescription: "English description",
+          },
+          de: {
+            siteName: "Brand DE",
+            titleTemplate: "{pageTitle} | {siteName} | Freelancer",
+            subhead: "German subhead",
+          },
+        },
+      }),
+      "Fallback Name",
+    );
+
+    expect(settings.locales.en.siteName).toBe("Brand EN");
+    expect(settings.locales.en.titleTemplate).toBe("{pageTitle} - {siteName}");
+    expect(settings.locales.en.siteDescription).toBe("English description");
+    expect(settings.locales.en.subhead).toBe("");
+    expect(settings.locales.ar.siteName).toBe("Fallback Name");
+    expect(settings.locales.ar.titleTemplate).toBe("{pageTitle} | {siteName}");
+    expect(settings.locales.de.siteDescription).toBe("Multilingual Next.js base project");
+    expect(settings.locales.de.titleTemplate).toBe("{pageTitle} | {siteName} | Freelancer");
+    expect(settings.locales.de.subhead).toBe("German subhead");
+  });
+
+  it("falls back when stored json is invalid", () => {
+    const settings = parseSiteSettingsValue("{invalid-json", "Fallback Name");
+
+    expect(settings).toEqual(buildDefaultSiteSettings("Fallback Name"));
+  });
+});