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/admin/components/AdminHeader.js

@@ -3,7 +3,7 @@
 import React from 'react';
 import { Menu, Transition } from '@headlessui/react';
 import { Fragment } from 'react';
-import { ChevronDownIcon } from '../../../shared/Icons.js';
+import { ChevronDownIcon } from '@zen/core/shared/icons';
 import { useRouter } from 'next/navigation';
 import ThemeToggle from './ThemeToggle';
 

src/features/admin/components/AdminSidebar.js

@@ -3,8 +3,8 @@
 import React, { useState, useEffect } from 'react';
 import Link from 'next/link';
 import { usePathname } from 'next/navigation';
-import * as Icons from '../../../shared/Icons.js';
-import { ChevronDownIcon } from '../../../shared/Icons.js';
+import * as Icons from '@zen/core/shared/icons';
+import { ChevronDownIcon } from '@zen/core/shared/icons';
 
 /**
  * Resolve icon name (string) to icon component

src/features/admin/components/ThemeToggle.js

@@ -1,7 +1,7 @@
 'use client';
 
 import { useState, useEffect } from 'react';
-import { Sun01Icon, Moon02Icon, SunCloud02Icon, MoonCloudIcon } from '../../../shared/Icons.js';
+import { Sun01Icon, Moon02Icon, SunCloud02Icon, MoonCloudIcon } from '@zen/core/shared/icons';
 
 function getNextTheme(current) {
     const systemIsDark = window.matchMedia('(prefers-color-scheme: dark)').matches;

src/features/admin/components/pages/DashboardPage.js

@@ -1,7 +1,7 @@
 'use client';
 
-import { StatCard } from '../../../../shared/components';
-import { UserMultiple02Icon } from '../../../../shared/Icons.js';
+import { StatCard } from '@zen/core/shared/components';
+import { UserMultiple02Icon } from '@zen/core/shared/icons';
 
 export default function DashboardPage({ user, stats }) {
   const loading = !stats;

src/features/admin/components/pages/ProfilePage.js

@@ -1,7 +1,7 @@
 'use client';
 
 import React, { useState, useEffect, useRef } from 'react';
-import { Card, Input, Button } from '../../../../shared/components';
+import { Card, Input, Button } from '@zen/core/shared/components';
 import { useToast } from '@zen/core/toast';
 
 const ProfilePage = ({ user: initialUser }) => {

src/features/admin/components/pages/UserEditPage.js

@@ -2,7 +2,7 @@
 
 import React, { useState, useEffect } from 'react';
 import { useRouter } from 'next/navigation';
-import { Button, Card, Input, Select, Loading } from '../../../../shared/components';
+import { Button, Card, Input, Select, Loading } from '@zen/core/shared/components';
 import { useToast } from '@zen/core/toast';
 
 /**

src/features/admin/components/pages/UsersPage.js

@@ -2,8 +2,8 @@
 
 import React, { useState, useEffect } from 'react';
 import { useRouter } from 'next/navigation';
-import { Card, Table, StatusBadge, Pagination, Button } from '../../../../shared/components';
-import { PencilEdit01Icon } from '../../../../shared/Icons.js';
+import { Card, Table, StatusBadge, Pagination, Button } from '@zen/core/shared/components';
+import { PencilEdit01Icon } from '@zen/core/shared/icons';
 import { useToast } from '@zen/core/toast';
 
 const UsersPageClient = () => {