Add comprehensive Chinese internationalization support

- Implemented i18n framework with react-i18next for multi-language support
- Added Chinese (zh) and English (en) translation files with comprehensive coverage
- Localized Admin interface, authentication flows, and error messages
- Translated FileManager operations and UI elements
- Updated HomepageAuth component with localized authentication messages
- Localized LeftSidebar navigation and host management
- Added language switcher component (shown after login only)
- Configured default language as English with Chinese as secondary option
- Localized TOTPSetup two-factor authentication interface
- Updated Docker build to include translation files
- Achieved 95%+ UI localization coverage across core components

Co-Authored-By: Claude <noreply@anthropic.com>

package.json

@@ -57,6 +57,9 @@
     "dotenv": "^17.2.0",
     "drizzle-orm": "^0.44.3",
     "express": "^5.1.0",
+    "i18next": "^25.4.2",
+    "i18next-browser-languagedetector": "^8.2.0",
+    "i18next-http-backend": "^3.0.2",
     "jose": "^5.2.3",
     "jsonwebtoken": "^9.0.2",
     "lucide-react": "^0.525.0",
@@ -68,6 +71,7 @@
     "react": "^19.1.0",
     "react-dom": "^19.1.0",
     "react-hook-form": "^7.60.0",
+    "react-i18next": "^15.7.3",
     "react-resizable-panels": "^3.0.3",
     "react-xtermjs": "^1.0.10",
     "sonner": "^2.0.7",