v0.4.2

This patch lets installers safely cancel a first-agent request before setup makes changes, including after an app restart. A cancelled request cannot start later through a stale retry. Existing agents and partially completed setup are preserved.

Optional runtime compatibility checks now show the selected executable and version. OpenCode diagnostics distinguish an older selected version from an unreadable or failed version probe, making PATH conflicts easier to identify.

Upgrade through your installer or uv tool upgrade agent-backbone. The running service must also load 0.4.2 before consumers can use the cancellation endpoint. With automatic reload enabled (the default), it checks for the upgrade every 60 seconds and reloads gracefully. Installers should verify the running version and preserve saved cancellation intent while waiting; upgrading the CLI alone is not confirmation. Existing credentials and configuration are preserved.