♻️ refactor(web): migrate React modules from .js to .jsx and align entrypoint

- Rename React components/pages/utilities that contain JSX to `.jsx` across `web/src`
- Update import paths and re-exports to match new `.jsx` extensions
- Fix Vite entry by switching `web/index.html` from `/src/index.js` to `/src/index.jsx`
- Verified remaining `.js` files are plain JS (hooks/helpers/constants) and do not require JSX
- No runtime behavior changes; extension and reference alignment only

Context: Resolves the Vite pre-transform error caused by the stale `/src/index.js` entry after migrating to `.jsx`.

web/src/components/layout/HeaderBar/ActionButtons.jsx

@@ -18,11 +18,11 @@ For commercial licensing, please contact support@quantumnous.com
 */
 
 import React from 'react';
-import NewYearButton from './NewYearButton.js';
-import NotificationButton from './NotificationButton.js';
-import ThemeToggle from './ThemeToggle.js';
-import LanguageSelector from './LanguageSelector.js';
-import UserArea from './UserArea.js';
+import NewYearButton from './NewYearButton';
+import NotificationButton from './NotificationButton';
+import ThemeToggle from './ThemeToggle';
+import LanguageSelector from './LanguageSelector';
+import UserArea from './UserArea';
 
 const ActionButtons = ({
   isNewYear,

web/src/components/layout/HeaderBar/HeaderLogo.jsx

@@ -20,7 +20,7 @@ For commercial licensing, please contact support@quantumnous.com
 import React from 'react';
 import { Link } from 'react-router-dom';
 import { Typography, Tag } from '@douyinfe/semi-ui';
-import SkeletonWrapper from './SkeletonWrapper.js';
+import SkeletonWrapper from './SkeletonWrapper';
 
 const HeaderLogo = ({
   isMobile,

web/src/components/layout/HeaderBar/Navigation.jsx

@@ -19,7 +19,7 @@ For commercial licensing, please contact support@quantumnous.com
 
 import React from 'react';
 import { Link } from 'react-router-dom';
-import SkeletonWrapper from './SkeletonWrapper.js';
+import SkeletonWrapper from './SkeletonWrapper';
 
 const Navigation = ({
   mainNavLinks,

web/src/components/layout/HeaderBar/UserArea.jsx

@@ -32,8 +32,8 @@ import {
   IconCreditCard,
   IconKey,
 } from '@douyinfe/semi-icons';
-import { stringToColor } from '../../../helpers/index.js';
-import SkeletonWrapper from './SkeletonWrapper.js';
+import { stringToColor } from '../../../helpers';
+import SkeletonWrapper from './SkeletonWrapper';
 
 const UserArea = ({
   userState,

web/src/components/layout/HeaderBar/index.jsx

@@ -18,14 +18,14 @@ For commercial licensing, please contact support@quantumnous.com
 */
 
 import React from 'react';
-import { useHeaderBar } from '../../../hooks/common/useHeaderBar.js';
-import { useNotifications } from '../../../hooks/common/useNotifications.js';
-import { useNavigation } from '../../../hooks/common/useNavigation.js';
-import NoticeModal from '../NoticeModal.js';
-import MobileMenuButton from './MobileMenuButton.js';
-import HeaderLogo from './HeaderLogo.js';
-import Navigation from './Navigation.js';
-import ActionButtons from './ActionButtons.js';
+import { useHeaderBar } from '../../../hooks/common/useHeaderBar';
+import { useNotifications } from '../../../hooks/common/useNotifications';
+import { useNavigation } from '../../../hooks/common/useNavigation';
+import NoticeModal from '../NoticeModal';
+import MobileMenuButton from './MobileMenuButton';
+import HeaderLogo from './HeaderLogo';
+import Navigation from './Navigation';
+import ActionButtons from './ActionButtons';
 
 const HeaderBar = ({ onMobileMenuToggle, drawerOpen }) => {
   const {