[RL] add pause, update_weights, resume interface for async RL

[mitu626]

Motivation

1. RL异步异置场景通过RDMA权重原地更新能力。
2. 在FastDeploy内部，支持 api-server <--> engine <--> worker 之间控制信号通信机制。

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Modifications

1. 控制信号通信：
   • api-server <--> engine：复用当前zmq通信机制，新增ControlRequest、ControlResponse类型。
   • engine ---> worker：复用当前通信机制（engine_worker_queue)，插入 ControlRequest 请求
   • engine <--- worker：基于 fmq.Queue 新增每个TP rank和engine的通信queue，支持每个TP rank返回自己的执行结果 ControlResponse
2. 新增接口
   • /v1/pause: 推理引擎不再响应推理请求，当前正在执行的推理请求会被打断。
   • /v1/update_weights: 基于RDMA远程同步权重，并原地更新权重
   • /v1/resume：回归推理引擎继续相应推理请求
   • /v1/is_paused: 查看当前推理引擎状态

其他说明：

1. 当前控制信号执行会阻塞推理请求的处理，在权重更新场景下本身需要pause，因此无影响，后续需要升级支持可选异步，不阻塞推理请求。
2. 当前worker ---> engine 控制信号返回信道和推理请求输出结果的返回信道独立，后续需要考虑是否可以合并以简化系统。

Usage or Command

1. 服务启动时，新增参数 --load-strategy "rsync" --rsync-config '{"xxxx":"xxxx"}'
2. 接口调用：
   • pause：curl -XPOST http://host:port/v1/pause
   • update_weights curl-XPOST http://host:port/v1/update_weights -d '{"version": "xxx", "rsync_config": {}}'
   • resume: curl -XPOST http://host:port/v1/resume
   • is_paused: curl -XGET http://host:port/v1/is_paused

说明：

• rsync需要的模型版本，默认从模型路径下的文件内读取 {model}/version.txt，支持调用接口时通过参数指定
• rsync依赖的config支持在启动时传入默认配置参数，也支持调用接口时通过参数指定

Accuracy Tests

Checklist

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  • Tag list: [[FDConfig],[APIServer],[Engine], [Scheduler], [PD Disaggregation], [Executor], [Graph Optimization], [Speculative Decoding], [RL], [Models], [Quantization], [Loader], [OP], [KVCache], [DataProcessor], [BugFix], [Docs], [CI], [Optimization], [Feature], [Benchmark], [Others], [XPU], [HPU], [GCU], [DCU], [Iluvatar], [Metax]]
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• Add unit tests. Please write the reason in this PR if no unit tests.
• Provide accuracy results.
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