feat: wire i18n services and shared UI

server/i18n/locale.ts

@@ -0,0 +1,28 @@
+import type { TextDirection } from "../../lib/i18n";
+
+export const LOCALE_COOKIE = "neta_locale";
+export const LOCALE_COOKIE_MAX_AGE = 60 * 60 * 24 * 365;
+export const DEFAULT_TEXT_DIRECTION: TextDirection = "ltr";
+
+export function normalizeLocaleCode(value: string | null | undefined): string | null {
+  if (!value) return null;
+  const normalized = value.trim();
+  return /^[a-z]{2}(?:-[A-Z]{2}[0-9]?)?$/.test(normalized) ? normalized : null;
+}
+
+export function directionForLocale(locale: string, explicit?: TextDirection | null): TextDirection {
+  if (explicit) return explicit;
+  return /^(ar|fa|he|ur)(-|$)/.test(locale) ? "rtl" : DEFAULT_TEXT_DIRECTION;
+}
+
+export function buildLocaleCookie(value: string) {
+  return {
+    name: LOCALE_COOKIE,
+    value,
+    maxAge: LOCALE_COOKIE_MAX_AGE,
+    sameSite: "lax" as const,
+    path: "/",
+    httpOnly: false,
+    secure: process.env.NODE_ENV === "production",
+  };
+}