chore: rename package from @hykocx/zen to @zen/core

Update all references across source files, documentation, and
configuration to reflect the new package scope and name. This includes
updating `.npmrc` registry config, install instructions, module
examples, and all import path comments throughout the codebase.

src/features/provider/ZenProvider.js

@@ -1,7 +1,7 @@
 'use client';
 
 import { useState } from 'react';
-import { ToastProvider, ToastContainer } from '@hykocx/zen/toast';
+import { ToastProvider, ToastContainer } from '@zen/core/toast';
 import { registerExternalModulePages } from '../../modules/modules.pages.js';
 
 /**