Document Claude ACP review backend

[xingyaoww]

Summary

• Document Claude Agent ACP as a supported ACP review backend.
• Show the self-hosted runner setup that preinstalls @agentclientprotocol/claude-agent-acp and starts the installed claude-agent-acp binary.
• Clarify that Claude credentials must come from runner bootstrap/secrets and must not be committed.
• Keep Codex ACP as the default ACP example while documenting how to opt into Claude Agent ACP.

Validation

• python3 scripts/sync_extensions.py --check
• uv run --with pytest --with openhands-sdk --with openhands-tools --with lmnr pytest -q tests/test_pr_review_prompt.py tests/test_pr_review_review_context.py (14 passed)
• Local ACP smoke test using Claude Code 2.1.119 returned the expected response through openhands.sdk.agent.ACPAgent
• Self-hosted workflow validation completed successfully after preinstalling @agentclientprotocol/claude-agent-acp@0.31.1 and running acp-command: claude-agent-acp

Notes

This is stacked on top of #210, which contains the generic ACP review backend support.

[xingyaoww]

Local Claude Agent ACP smoke test passed.

Configuration used:

• ACP command: npx -y @agentclientprotocol/claude-agent-acp
• Claude Code: 2.1.119
• SDK package: openhands-sdk @ git+https://github.com/OpenHands/software-agent-sdk.git@feat/acp-skill-prompt-adapter#subdirectory=openhands-sdk
• ACP model: sonnet

Sanitized output excerpt:

ACP server initialized: agent_name='@agentclientprotocol/claude-agent-acp', agent_version='0.31.1'
Setting ACP session mode: bypassPermissions
Sending ACP prompt (timeout=240s, msg=62 chars)
ACP prompt returned in 1.7s
MessageEvent user: Reply with exactly this token and no other text: CLAUDE_ACP_OK
SystemPromptEvent agent: This conversation is powered by an ACP server.
MessageEvent agent: assistant: CLAUDE_ACP_OK
ActionEvent agent: FinishAction
ObservationEvent environment: Result: CLAUDE_ACP_OK

No credential files were committed or included in the PR.