feat(i18n): add Lingui runtime and development tooling

- add SSR-safe I18nProvider, Translate, locale hooks, catalog activation, and typed runtime APIs

- add consumer-owned Lingui configuration helpers and a CLI for locale creation, extraction, compilation, and project discovery

- add catalog read/write services plus a Vite development API plugin scoped to each consuming application

- add the portal-based I18nDevtool, message editor, dark-theme tracking, and standalone Message Studio

- document the consumer workflow and cover runtime, configuration, catalog, CLI, and Devtool behavior with tests

packages/i18n/src/devtool/message-repository.tsx

@@ -0,0 +1,39 @@
+import * as React from "react"
+
+import type { MessageRepository } from "./types"
+
+const MessageRepositoryContext = React.createContext<MessageRepository | null>(
+  null
+)
+
+export interface MessageRepositoryProviderProps {
+  children: React.ReactNode
+  repository: MessageRepository
+}
+
+export function MessageRepositoryProvider({
+  children,
+  repository,
+}: MessageRepositoryProviderProps) {
+  return (
+    <MessageRepositoryContext.Provider value={repository}>
+      {children}
+    </MessageRepositoryContext.Provider>
+  )
+}
+
+export function useMessageRepository() {
+  const repository = React.useContext(MessageRepositoryContext)
+
+  if (!repository) {
+    throw new Error(
+      "MessagePanel requires a MessageRepositoryProvider or a repository prop."
+    )
+  }
+
+  return repository
+}
+
+export function useOptionalMessageRepository() {
+  return React.useContext(MessageRepositoryContext)
+}