* feat(agent.launch): a launch can name chat or terminal, and the CLI gets --surface chat|terminal
agent.launch gains an optional `surface` field, read by hosts advertising
agent.launch.surface.v1. `terminal` always runs the agent's CLI; `chat` runs a
chat even when the user's default is a terminal, and one the host can prove it
cannot open is refused with a typed no-effects error before anything is
created, so a retry answers with the same refusal. The pick is part of the
replay fingerprint. `orca agent launch` and `orca worktree create --agent`
accept --surface chat|terminal and refuse it on a host that would drop it,
including the legacy worktree.create fallback.
* test(agent.launch): pin the surface pick beside the other pre-start failures
* fix(agent.launch): settle requested surfaces from resolved workspace facts
* fix(agent.launch): describe fallback boundaries and correct test types
