0.1.0

Added

• beacon auth logs in to Isambard Keycloak as the k8s-gateway client with the OAuth 2.0 device flow.
• beacon token prints the cached access token for the Kubernetes gateway, or tells you to run beacon auth if it has expired.
• beacon whoami shows the token's claims, and beacon logout deletes the cached token.
• An example examples/opencode/opencode.json for using a gateway-hosted model with opencode.