Add the iroh-driver spec; trim and restructure the mvp-system orchestrator and
mvp-chat specs. Reframe prompt RPC as the prompt-engine contract in mvp_chat.md; add an
iroh-driver dependency; minor datastream_transport cleanup.
Signed-off-by: Zachery Aaron Shores-Chmielewski <zacheryasc@gmail.com>
Add mvp-system/src/mvp_chat.rs with a run_from_args entrypoint wiring swactor runtime,
dashboard, chat datastream, and a PromptLoop. Add a mock integration test; refresh
mvp-chat and MVP_SYSTEM specs.
Signed-off-by: Zachery Aaron Shores-Chmielewski <zacheryasc@gmail.com>
