Update navigation links to replace 'Join Now' button with 'Login' link and add translations for login in English and Chinese

src/components/Nav.tsx

@@ -27,7 +27,7 @@ function Nav({ currentPage }: NavProps) {
           <Link to="/friends" className={currentPage === 'friends' ? 'active' : ''}>{t('nav.friends')}</Link>
           <ThemeToggle />
           <LanguageSelector />
-          <button className="join-btn">{t('nav.joinNow')}</button>
+          <a href="/api/authenticator/steam/login" className="join-btn">{t('nav.login')}</a>
         </div>
       </div>
     </nav>

src/locales/en.json

@@ -7,7 +7,8 @@
     "git": "Git",
     "forum": "Forum",
     "friends": "Friend",
-    "joinNow": "Join Now"
+    "joinNow": "Join Now",
+    "login": "Login"
   },
   "hero": {
     "title": "Welcome to the Ultimate",

src/locales/zh.json

@@ -6,7 +6,8 @@
     "git": "开源",
     "forum": "论坛",
     "friends": "友链",
-    "joinNow": "立即加入"
+    "joinNow": "立即加入",
+    "login": "登录"
   },
   "hero": {
     "title": "欢迎来到终极",