Use German umlauts in landing copy

tests/landing-content.test.mjs

@@ -7,7 +7,26 @@ const componentPath = new URL("../src/components/canva-landing.tsx", import.meta
 test("Canva landing component contains the core brief anchors", async () => {
   const source = await readFile(componentPath, "utf8");
 
-  for (const phrase of ["Projektbrief", "01", "Website", "Kontakt"]) {
+  for (const phrase of ["Projektbrief", "01", "Website", "Kontakt", "für", "müssen", "Änderungen"]) {
     assert.match(source, new RegExp(phrase));
   }
 });
+
+test("Canva landing component uses real German umlauts in visible copy", async () => {
+  const source = await readFile(componentPath, "utf8");
+
+  for (const asciiFallback of [
+    "fuer",
+    "muessen",
+    "spaetere",
+    "Aenderungen",
+    "glaubwuerdig",
+    "naechste",
+    "Agenturlaerm",
+    "Erzaehlen",
+    "Saetze",
+    "Rueckmeldung",
+  ]) {
+    assert.doesNotMatch(source, new RegExp(asciiFallback));
+  }
+});