Migrate Agent/Relay/Tunnel handlers from compat {success,message,data}
to response.OK and response.Abort* with real HTTP status codes. Remove
the compat package and update openflare-agent, openflare-relay, and
openflared clients to parse {error_msg,data}.
Remove the /openflare prefix from management APIs (/api/v1/d/*) and move
Agent, Relay, and Tunnel protocol endpoints under /api/v1. Update Wavelet
frontend services and node client binaries to match.
ryan