Add i18n support: per-locale catalogs, URL-driven locale, translated core and examples

src/i18n/english.ts

@@ -0,0 +1,17 @@
+// The shipped en-US catalog, ready to use without loading anything from disk. This is what the
+// host falls back to wherever the loaded catalogs haven't been wired — a context built ad hoc, a
+// view model built outside a request, an app created without `i18n` — so an unwired path renders
+// real English rather than bare keys. server.ts replaces it with the discovered catalogs at boot.
+
+import { DEFAULT_LOCALE } from "./catalog.ts";
+import enUS from "./locales/en-US.ts";
+import { createI18n, type I18n } from "./runtime.ts";
+import { createTranslator, type Translate } from "./translate.ts";
+
+export const ENGLISH: Translate = createTranslator({ catalogs: [enUS], locale: DEFAULT_LOCALE });
+
+export const ENGLISH_I18N: I18n = createI18n({
+  available: [DEFAULT_LOCALE],
+  core: new Map([[DEFAULT_LOCALE, enUS]]),
+  plugins: new Map(),
+});