feat: add i18n and avatar upload

apps/backend/src/modules/images/storage.service.ts

@@ -25,6 +25,20 @@ export async function saveUploadedImage(
   return { imageUrl: relative };
 }
 
+export async function saveUploadedAvatar(
+  userId: string,
+  mime: string,
+  buffer: Buffer,
+): Promise<{ imageUrl: string }> {
+  const ext = MIME_TO_EXT[mime];
+  if (!ext) throw new ValidationError('Unsupported image type');
+  const filename = `${userId}-${nanoid(8)}.${ext}`;
+  const relative = `/uploads/avatar/${filename}`;
+  const absPath = resolve(env.UPLOADS_DIR, 'avatar', filename);
+  await writeFile(absPath, buffer);
+  return { imageUrl: relative };
+}
+
 export async function deleteLocalImageIfAny(imageUrl: string | null): Promise<void> {
   if (!imageUrl) return;
   if (!imageUrl.startsWith('/uploads/')) return;