Add Forum page with layout, mock data, and routing; update navigation and localization

src/components/Nav.tsx

@@ -21,7 +21,7 @@ function Nav({ currentPage }: NavProps) {
           <Link to="/servers" className={currentPage === 'servers' ? 'active' : ''}>{t('nav.servers')}</Link>
           <Link to="/blog" className={currentPage === 'blog' ? 'active' : ''}>{t('nav.blog')}</Link>
           <a href="https://git.cialloo.com" className={currentPage === 'git' ? 'active' : ''}>{t('nav.git')}</a>
-          <a href="/#forum" className={currentPage === 'forum' ? 'active' : ''}>{t('nav.forum')}</a>
+          <Link to="/forum" className={currentPage === 'forum' ? 'active' : ''}>{t('nav.forum')}</Link>
           <Link to="/friends" className={currentPage === 'friends' ? 'active' : ''}>{t('nav.friends')}</Link>
           <ThemeToggle />
           <LanguageSelector />