refactor(auth): apply fixed public instance locale resolution to auth pages

app/invite/[token]/actions.ts

@@ -1,13 +1,10 @@
 "use server";
 
-import { cookies } from "next/headers";
 import { redirect } from "next/navigation";
 import {
   acceptPortalInvitation,
-  getPortalInvitationPreview,
   PortalInvitationError,
 } from "@/server/auth/invitations";
-import { buildLocaleCookie } from "@/server/i18n/locale";
 
 function inviteErrorCode(error: unknown): string {
   if (!(error instanceof PortalInvitationError)) return "auth.messages.portalInviteFailed";
@@ -27,7 +24,5 @@ export async function acceptInvitation(formData: FormData) {
     redirect(`/invite/${encodeURIComponent(token)}?error=true&code=${inviteErrorCode(error)}`);
   }
 
-  const locale = getPortalInvitationPreview(token)?.locale ?? "tr";
-  (await cookies()).set(buildLocaleCookie(locale));
   redirect("/login?code=auth.invite.success");
 }

app/invite/[token]/page.tsx

@@ -9,6 +9,7 @@ import { Input, Label } from "poyraz-ui/atoms";
 import { Alert, AlertDescription } from "poyraz-ui/molecules";
 import { getPortalInvitationPreview } from "@/server/auth/invitations";
 import { getPublicBranding } from "@/server/branding/runtime";
+import { resolveInvitationLocale } from "@/server/i18n/resolver";
 import { createTranslator } from "@/server/i18n/translator";
 
 export const dynamic = "force-dynamic";
@@ -28,7 +29,8 @@ export default async function InvitationPage({
     notFound();
   }
 
-  const t = createTranslator(invitation.locale, ["auth"]).t;
+  const resolvedLocale = await resolveInvitationLocale(invitation.locale);
+  const t = createTranslator(resolvedLocale.locale, ["auth"]).t;
   const query = await searchParams;
   const queryCode = query.code ?? null;
   const queryMessage = queryCode ? t(queryCode) : query.message;