Module session_manager 

Session Manager with backend version tracking

This module implements ProxyAwareSessionManager that integrates with ProxyHandler’s version control mechanism to automatically invalidate sessions when the backend reconnects.

Architecture

ProxyAwareSessionManager
├── LocalSessionManager (rmcp 提供的基础实现)
├── ProxyHandler (Arc, 访问 backend_version)
└── DashMap<SessionId, SessionMetadata> (跟踪 session 创建时的版本)

工作流程：
1. create_session: 记录当前 backend_version
2. resume: 检查版本是否匹配
   - 匹配 → 正常 resume
   - 不匹配 → 返回 NotFound，客户端重新创建 session

Structs

ProxyAwareSessionManager

感知代理状态的 SessionManager