Function interactive 

pub async fn interactive(
    harness: &AgentHarness,
    event_rx: Option<Receiver<AgentEvent>>,
    args: &Args,
    model_catalog: Vec<Model>,
    initial: Option<String>,
    extra_messages: &[String],
    theme: Option<&str>,
) -> i32

interactive mode: uses TUI if terminal supports it, falls back to minimal REPL.

event_rx carries the live AgentEvent stream (drained by the TUI to render streaming responses). The REPL fallback ignores it.

model_catalog is the resolved provider’s full model list, passed through so the TUI’s /model selector can display available models (read-only — v1 does not switch models mid-session; see docs/m6-cli-open-questions.md).