🎛️ refactor: HeaderBar into modular components, add shared skeletons, and primary-colored nav hover

Summary
- Split HeaderBar into maintainable components and hooks
- Centralized skeleton loading UI via a reusable SkeletonWrapper
- Improved navigation UX with primary-colored hover indication
- Preserved API surface and passed linters

Why
- Improve readability, reusability, and testability of the header
- Remove duplicated skeleton logic across files
- Provide clearer hover feedback consistent with the theme

What’s changed
- Components (web/src/components/layout/HeaderBar/)
  - New container: index.js
  - New UI components: HeaderLogo.js, Navigation.js, ActionButtons.js, UserArea.js, MobileMenuButton.js, NewYearButton.js, NotificationButton.js, ThemeToggle.js, LanguageSelector.js
  - New shared skeleton: SkeletonWrapper.js
  - Updated entry: HeaderBar.js now re-exports ./HeaderBar/index.js
- Hooks (web/src/hooks/common/)
  - New: useHeaderBar.js (state and actions for header)
  - New: useNotifications.js (announcements state, unread calc, open/close)
  - New: useNavigation.js (main nav link config)
- Skeleton refactor
  - Navigation.js: replaced inline skeletons with <SkeletonWrapper type="navigation" .../>
  - UserArea.js: replaced inline skeletons with <SkeletonWrapper type="userArea" .../>
  - HeaderLogo.js: replaced image/title skeletons with <SkeletonWrapper type="image"/>, <SkeletonWrapper type="title"/>
- Navigation hover UX
  - Added primary-colored hover to nav items for clearer pointer feedback
  - Final hover style: hover:text-semi-color-primary (kept rounded + transition classes)

Non-functional
- No breaking API changes; HeaderBar usage stays the same
- All modified files pass lint checks

Notes for future work
- SkeletonWrapper is extensible: add new cases (e.g., card) in one place
- Components are small and test-friendly; unit tests can be added per component

Affected files (key)
- web/src/components/layout/HeaderBar.js
- web/src/components/layout/HeaderBar/index.js
- web/src/components/layout/HeaderBar/Navigation.js
- web/src/components/layout/HeaderBar/UserArea.js
- web/src/components/layout/HeaderBar/HeaderLogo.js
- web/src/components/layout/HeaderBar/ActionButtons.js
- web/src/components/layout/HeaderBar/MobileMenuButton.js
- web/src/components/layout/HeaderBar/NewYearButton.js
- web/src/components/layout/HeaderBar/NotificationButton.js
- web/src/components/layout/HeaderBar/ThemeToggle.js
- web/src/components/layout/HeaderBar/LanguageSelector.js
- web/src/components/layout/HeaderBar/SkeletonWrapper.js
- web/src/hooks/common/useHeaderBar.js
- web/src/hooks/common/useNotifications.js
- web/src/hooks/common/useNavigation.js

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

@@ -0,0 +1,88 @@
+/*
+Copyright (C) 2025 QuantumNous
+
+This program is free software: you can redistribute it and/or modify
+it under the terms of the GNU Affero General Public License as
+published by the Free Software Foundation, either version 3 of the
+License, or (at your option) any later version.
+
+This program is distributed in the hope that it will be useful,
+but WITHOUT ANY WARRANTY; without even the implied warranty of
+MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+GNU Affero General Public License for more details.
+
+You should have received a copy of the GNU Affero General Public License
+along with this program. If not, see <https://www.gnu.org/licenses/>.
+
+For commercial licensing, please contact support@quantumnous.com
+*/
+
+import React from 'react';
+import { Link } from 'react-router-dom';
+import SkeletonWrapper from './SkeletonWrapper.js';
+
+const Navigation = ({
+  mainNavLinks,
+  isMobile,
+  isLoading,
+  userState
+}) => {
+  const renderNavLinks = () => {
+    const baseClasses = 'flex-shrink-0 flex items-center gap-1 font-semibold rounded-md transition-all duration-200 ease-in-out';
+    const hoverClasses = 'hover:text-semi-color-primary';
+    const spacingClasses = isMobile ? 'p-1' : 'p-2';
+
+    const commonLinkClasses = `${baseClasses} ${spacingClasses} ${hoverClasses}`;
+
+    return mainNavLinks.map((link) => {
+
+      const linkContent = <span>{link.text}</span>;
+
+      if (link.isExternal) {
+        return (
+          <a
+            key={link.itemKey}
+            href={link.externalLink}
+            target='_blank'
+            rel='noopener noreferrer'
+            className={commonLinkClasses}
+          >
+            {linkContent}
+          </a>
+        );
+      }
+
+      let targetPath = link.to;
+      if (link.itemKey === 'console' && !userState.user) {
+        targetPath = '/login';
+      }
+
+      return (
+        <Link
+          key={link.itemKey}
+          to={targetPath}
+          className={commonLinkClasses}
+        >
+          {linkContent}
+        </Link>
+      );
+    });
+  };
+
+  return (
+    <nav className="flex flex-1 items-center gap-1 lg:gap-2 mx-2 md:mx-4 overflow-x-auto whitespace-nowrap scrollbar-hide">
+      <SkeletonWrapper
+        loading={isLoading}
+        type="navigation"
+        count={4}
+        width={60}
+        height={16}
+        isMobile={isMobile}
+      >
+        {renderNavLinks()}
+      </SkeletonWrapper>
+    </nav>
+  );
+};
+
+export default Navigation;