feat(i18n): integrate internationalization into sidebar, title bar, and settings components

- Added useI18n hook to Sidebar and TitleBar components for translation support.
- Updated sidebar navigation items to use translation keys instead of hardcoded labels.
- Enhanced TitleBar buttons with localized titles for minimize, maximize, and close actions.
- Expanded i18n constants to include new namespaces for sidebar and login.
- Implemented translation messages for sidebar, settings, and login components in English, Chinese, and Japanese.
- Refactored Knowledge and Skills pages to utilize useLocale for locale management.
- Updated Login page to display localized text for form labels, placeholders, and error messages.
- Enhanced Account and General settings panels with localized titles and descriptions.
- Modified SettingMenu to use translation keys for menu items.

src/components/layout/Sidebar.tsx

@@ -1,5 +1,6 @@
 import { useLocation, useNavigate } from 'react-router-dom';
 import { Book, Clock, Code, Cpu, House, Puzzle, Settings } from 'lucide-react';
+import { useI18n } from '../../i18n';
 import { NAV_ITEMS, normalizeWorkspacePath } from '../../router/routes';
 
 const MENU_MARKS: Record<string, typeof House> = {
@@ -15,6 +16,7 @@ const MENU_MARKS: Record<string, typeof House> = {
 export default function Sidebar() {
   const location = useLocation();
   const navigate = useNavigate();
+  const { t } = useI18n();
   const currentId = normalizeWorkspacePath(location.pathname);
 
   return (
@@ -53,7 +55,7 @@ export default function Sidebar() {
                   className="mt-[4px] mb-[8px] text-[14px] hover:text-[#2B7FFF]"
                   style={{ color: active ? '#2B7FFF' : '#525866' }}
                 >
-                  {item.label}
+                  {t(item.labelKey)}
                 </div>
               </button>
             </div>