fix: send account cookies when saving profile

frontend/src/app/page.tsx

@@ -1322,6 +1322,7 @@ export default function Home() {
     const birthPlace = selectedBirthPlace(nextProfile);
     const response = await fetch("/api/account", {
       method: "PATCH",
+      credentials: "same-origin",
       headers: { "content-type": "application/json" },
       body: JSON.stringify({
         name: nextProfile.name.trim() || null,

frontend/tests/profile-persistence.test.ts

@@ -5,6 +5,7 @@ import test from "node:test";
 test("upserts a missing profile when saving account details", () => {
   const source = readFileSync(new URL("../src/app/page.tsx", import.meta.url), "utf8");
   assert.match(source, /fetch\("\/api\/account",\s*\{\s*method:\s*"PATCH"/s);
+  assert.match(source, /credentials:\s*"same-origin"/);
 });
 
 test("account route upserts profiles with the server admin client", () => {