feat(skill): use V3 signing for ROS agent StartChat

[guima-why]

Summary

• sign the ROS Agent code transport with Tea OpenAPI ACS3-HMAC-SHA256 while preserving incremental SSE consumption
• remove --force from native CLI StartChat and StopChat calls so published CLI metadata is used
• update code-transport dependencies and cover V3 headers, credential sources, and CLI metadata availability

Validation

• uv run ruff check skills/alicloud-ros-agent/scripts/ros_agent.py tests/skill_bridge/test_alicloud_ros_agent_bridge.py tests/skill_bridge/test_start_chat_relay.py
• uv run pytest -q tests/skill_bridge — 225 passed, 7 skipped because the currently installed CLI metadata does not yet expose StartChat/StopChat
• Skill quick validation passed
• QoderWork code transport readiness and offline V3 signing checks passed; pre-release endpoint flow was manually verified