feat: add i18n with type safety

inertia/types/i18n.d.ts

@@ -0,0 +1,9 @@
+import 'i18next';
+import { resources } from '../i18n';
+
+declare module 'i18next' {
+  interface CustomTypeOptions {
+    returnNull: false;
+    resources: (typeof resources)['fr'];
+  }
+}

inertia/types/utils.d.ts

@@ -0,0 +1,24 @@
+type Join<K, P> = K extends string
+  ? P extends string
+    ? `${K}${'' extends P ? '' : '.'}${P}`
+    : never
+  : never;
+
+type Paths<T> = T extends object
+  ? {
+      [K in keyof T]-?: K extends string
+        ? `${K}` | Join<K, Paths<T[K]>>
+        : never;
+    }[keyof T]
+  : '';
+
+type Leaves<T> = T extends object
+  ? {
+      [K in keyof T]-?: Join<K, Leaves<T[K]>>;
+    }[keyof T]
+  : '';
+
+type RemoveSuffix<
+  Key extends string,
+  SuffixAfter extends string = '_',
+> = Key extends `${infer Prefix}${SuffixAfter}${string}` ? Prefix : Key;