Expand description
Extended slash commands for the VT TUI harness.
These live in a sibling module to super::registry to keep the catalog-
dependent and introspection commands isolated from the core command
plumbing. They are registered alongside the built-ins by
register_extra (called from register_all in the sibling registry
Every command here is self-contained: it owns its definition + execution
and receives a SlashCtx (session, handle, state). The model
catalog is reached via ctx.state.catalog (captured once at TUI startup);
credentials via the process-global shared_auth_storage().