refactor: reorganize package exports under namespaced paths

- Prefix feature exports with `features/` (auth, admin, provider)
- Prefix shared exports with `shared/` (components, icons, lib, config, logger, rate-limit)
- Add new explicit exports for `shared/logger`, `shared/config`, and `shared/rate-limit`
- Update internal imports to use package self-referencing (`@zen/core/shared/*`) instead of relative paths

src/features/auth/api.js

@@ -12,9 +12,8 @@ import { updateUser } from './lib/auth.js';
 import { uploadImage, deleteFile, generateUniqueFilename, getFileExtension, FILE_TYPE_PRESETS, FILE_SIZE_LIMITS, validateUpload } from '@zen/core/storage';
 
 const generateUserFilePath = (userId, category, filename) => `users/${userId}/${category}/${filename}`;
-import { fail, info } from '../../shared/lib/logger.js';
-import { defineApiRoutes } from '../../core/api/define.js';
-import { apiSuccess, apiError } from '../../core/api/respond.js';
+import { fail, info } from '@zen/core/shared/logger';
+import { defineApiRoutes, apiSuccess, apiError } from '@zen/core/api';
 
 /** Maximum number of users returned per paginated request */
 const MAX_PAGE_LIMIT = 100;