feat(package/locale): update for parity with lua

Support for nested locales (flattening) and getLocale function.

package/shared/index.ts

@@ -1 +1,8 @@
 export * from './resource';
+
+// https://www.raygesualdo.com/posts/flattening-object-keys-with-typescript-types/
+export type FlattenObjectKeys<T extends Record<string, unknown>, Key = keyof T> = Key extends string
+  ? T[Key] extends Record<string, unknown>
+    ? `${Key}.${FlattenObjectKeys<T[Key]>}`
+    : `${Key}`
+  : never;