Integrate Prisma for content; enhance SEO, i18n, and deployment workflows

Co-authored-by: dennis <dennis@konkol.net>

e2e/i18n.spec.ts

@@ -0,0 +1,17 @@
+import { test, expect } from "@playwright/test";
+
+test.describe("i18n routing", () => {
+  test("language switcher navigates between locales", async ({ page }) => {
+    await page.goto("/en", { waitUntil: "domcontentloaded" });
+
+    // Buttons are "EN"/"DE" in the header
+    const deButton = page.getByRole("button", { name: "DE" });
+    if (await deButton.count()) {
+      await deButton.click();
+      await expect(page).toHaveURL(/\/de(\/|$)/);
+    } else {
+      test.skip();
+    }
+  });
+});
+