feat: AI虚拟用户新闻互动系统 v1.3.0 初始提交

- 虚拟用户管理（昵称/头像/性别/简介/邮箱同步到目标平台）
- AI互动调度（点赞/收藏/评论/转发）
- 日志时间改为北京时间
- 评论达上限后继续执行点赞收藏转发
- 一键登出全部功能
- 浅色主题UI

backend/app/models/all_models.py

@@ -0,0 +1,19 @@
+# models package - re-export all models
+from app.models import (
+    VirtualUser, UserPersonality, InteractionRecord,
+    TokenStat, AIModelConfig, SystemConfig, LoginLog
+)
+
+# Aliases for import compatibility
+virtual_user = VirtualUser
+personality = UserPersonality
+interaction = InteractionRecord
+token_stat = TokenStat
+ai_model = AIModelConfig
+system_config = SystemConfig
+login_log = LoginLog
+
+__all__ = [
+    "VirtualUser", "UserPersonality", "InteractionRecord",
+    "TokenStat", "AIModelConfig", "SystemConfig", "LoginLog",
+]