Function extract_contracts 

pub fn extract_contracts(
    prism: &Infigraph,
    service_name: &str,
) -> Result<Vec<Contract>>

Extract HTTP route contracts from a project’s graph.

Sources (in priority order):

1. Route symbols (kind=‘Route’) — from call-expression routing (Express, Gin, etc.)
2. Decorated functions — docstring contains route decorator (@app.route, #[get], etc.)
3. Heuristic detect_routes fallback