- Add onCreateCommand lifecycle hook (parsed, resolved, exposed as on_create_commands)
- Expose build.args on DevcontainerConfig for docker build --build-arg
- Wire containerEnv into generated Dockerfile as ENV directives (remoteEnv overrides on collision)
- Support dockerComposeFile as array of paths with merge semantics (last wins for image/build/user, ports accumulate, env overrides)
- Update DEVCONTAINER-COMPATIBILITY.md and INTEGRATION.md docs
- Add e2e tests with realistic Python and compose project fixtures
Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>
