feat: Add PDM support with auth & i18n enhancements (#627)

* feat: Add PDM support with auth & i18n enhancements

1. Added PDM project dependency management
   - Created pyproject.toml for dependency definitions
   - Added PDM lock file for reproducible builds
   - Created .pdm-python for virtual environment management

2. Enhanced authentication & configuration
   - Added user validation in base configuration
   - Implemented streamlit-authenticator for login functionality
   - Updated config.example.toml with user authentication fields

3. Improved internationalization (i18n)
   - Updated translation files for multiple languages (en, de, pt, vi, zh)
   - Enhanced i18n support in the web UI
   - Standardized translation structure across language files

webui/i18n/zh.json

@@ -1,6 +1,14 @@
 {
   "Language": "简体中文",
   "Translation": {
+    "Login Required": "需要登录",
+    "Please login to access settings": "请登录后访问配置设置",
+    "Username": "用户名",
+    "Password": "密码",
+    "Login": "登录",
+    "Login Error": "登录错误",
+    "Incorrect username or password": "用户名或密码不正确",
+    "Please enter your username and password": "请输入用户名和密码",
     "Video Script Settings": "**文案设置**",
     "Video Subject": "视频主题（给定一个关键词，:red[AI自动生成]视频文案）",
     "Script Language": "生成视频脚本的语言（一般情况AI会自动根据你输入的主题语言输出）",