[Feature Request] Implement RedisStateService to Align with Python Runtime

[xuehuitian45]

Description

The current Java runtime only provides MemoryStateService, which stores agent conversation states in memory. This is insufficient for:

• Multi-instance deployments
• Long-running sessions that survive restarts
• Production environments requiring persistence

The Python runtime already supports a RedisStateService for durable, distributed state management.

To ensure feature parity and production readiness, we propose adding a RedisStateService implementation in Java version that:

• Uses Redis as backend
• Supports TTL for automatic cleanup of stale sessions

Requirements

• Implement the existing StateService interface
• Minimal dependencies (avoid heavy frameworks)
• Thread-safe and performant for concurrent agent sessions

Scope Note

This is a straightforward port of the Python capability — no need for advanced features (e.g., clustering, Lua scripts) unless already present in Python version.