Two hook events arrive: session.start fires on terminal session start, and prompt.context is registered but has no emitter here.
Two new hook/event kinds, prompt.context and session.start, are now recognized for host-plugin messaging validation and payload-shape mapping. session.start is wired up: the terminal REPL calls a new _raiseSessionStart() unconditionally during session start, sending {loaded, surface: "terminal", interactive: true}, with a corresponding event schema payload of {cwd}. prompt.context appears in the same validation and telemetry site tables alongside other prompt-family events, but no direct emitter was found in this slice. Both event kinds were also added to the telemetry site registry alongside existing tool/prompt/agent/turn sites.