P1 Edge: 关节桥接重构 — 直接订阅 /joint_states + 资源跟随 + 吞吐优化

- HostNode 直接订阅 /joint_states (JointStateMsg)，绕过 JointRepublisher 中间人
- 新增 resource_pose 订阅，实现资源夹取跟随 (gripper attach/detach)
- 吞吐优化：死区过滤 (1e-4 rad)、抑频 (~20Hz)、增量 resource_poses
- JointRepublisher 修复 str→json.dumps (E1)
- communication.py 新增 publish_joint_state 抽象方法
- ws_client.py 实现 push_joint_state action 发送
- 57 项测试覆盖：关节分组、资源跟随、同类型多设备、优化行为

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

unilabos/ros/nodes/presets/joint_republisher.py

@@ -41,7 +41,7 @@ class JointRepublisher(BaseROS2DeviceNode):
             json_dict["velocity"]       = list(msg.velocity)
             json_dict["effort"]         = list(msg.effort)
 
-            self.msg.data = str(json_dict)
+            self.msg.data = json.dumps(json_dict)
             self.joint_repub.publish(self.msg)
             # print('-'*20)
             # print(self.msg.data)