feat(web): integrate localized application catalogs

- compose app, UI, and independently imported block catalogs from JSON configuration\n- persist the selected locale on the server and activate it without hydration flicker\n- add a flag-based language switcher and localized navigation descriptors\n- mount the redesigned i18n devtool only in development\n- regenerate English and Simplified Chinese catalogs and add switcher coverage

apps/web/src/i18n/app-locales.ts

@@ -0,0 +1,32 @@
+import type { LocaleDefinition } from "@workspace/i18n"
+
+export type AppLocale = "en" | "zh-Hans"
+export type AppLocaleCountry = "CN" | "US"
+
+export interface AppLocaleDefinition extends LocaleDefinition {
+  country: AppLocaleCountry
+  locale: AppLocale
+}
+
+export const DEFAULT_APP_LOCALE: AppLocale = "zh-Hans"
+
+export const appLocales = [
+  {
+    country: "US",
+    direction: "ltr",
+    languageTag: "en-US",
+    label: "English",
+    locale: "en",
+  },
+  {
+    country: "CN",
+    direction: "ltr",
+    languageTag: "zh-CN",
+    label: "简体中文",
+    locale: "zh-Hans",
+  },
+] as const satisfies readonly AppLocaleDefinition[]
+
+export function isAppLocale(value: unknown): value is AppLocale {
+  return appLocales.some((definition) => definition.locale === value)
+}