Add Docker smoke test CI with ACP handshake validation

[thepagent]

Problem

Recent regressions could have been caught by basic CI tests:

• fix: Dockerfiles pass config path as subcommand after clap migration #334 — CMD passes config path as subcommand after clap migration → container crashes on startup
• Agent binary naming — github-copilot vs copilot mismatch → No such file or directory

Currently there are no CI tests that verify the built Docker images actually work.

Proposed Solution

Add a GitHub Actions workflow that runs on PRs touching Dockerfile*, src/**, or Cargo.*. For each of the 5 image variants (default/kiro, claude, codex, gemini, copilot), test 3 layers:

1. openab binary — CMD regression check

Run the container with its default CMD and assert no "unrecognized subcommand" error.

2. Agent CLI exists

which <agent-binary> to verify the correct binary name is in PATH.

3. ACP initialize handshake

Pipe a JSON-RPC initialize request into the agent over stdio and validate the response contains agentInfo:

echo '{"jsonrpc":"2.0","id":1,"method":"initialize","params":{"protocolVersion":1,"clientCapabilities":{},"clientInfo":{"name":"ci-test","version":"0.0.1"}}}' \
  | timeout 30 docker run --rm -i --entrypoint <agent> <image> <args> \
  | head -1 | jq -e ".result.agentInfo.name"

No API keys or Discord tokens needed — initialize is an unauthenticated ACP handshake.

Test Matrix

Variant	Dockerfile	Agent Binary	Agent Args
kiro (default)	Dockerfile	kiro-cli	acp --trust-all-tools
claude	Dockerfile.claude	claude-agent-acp
codex	Dockerfile.codex	codex-acp
gemini	Dockerfile.gemini	gemini	--acp
copilot	Dockerfile.copilot	copilot	--acp

What this catches

• CMD/ENTRYPOINT regressions (fix: Dockerfiles pass config path as subcommand after clap migration #334)
• Wrong binary names in config
• Broken npm installs (missing or incompatible packages)
• ACP protocol incompatibilities after CLI version bumps

[github-actions]

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