feat: add i18n dictionaries and service data

Locale-aware EN/FR string dictionaries and the two-service data model
(CVE Watch with per-locale URLs, Convert with a single URL).

src/i18n/index.ts

@@ -0,0 +1,10 @@
+import { en } from './en';
+import { fr } from './fr';
+import type { Dictionary } from './en';
+import type { Locale } from './locale';
+
+const dictionaries: Record<Locale, Dictionary> = { en, fr };
+
+export function getDictionary(locale: Locale): Dictionary {
+  return dictionaries[locale];
+}