Function compute_hints_with_graph 

pub fn compute_hints_with_graph(
    graph: &CallGraph,
    test_chunks: &[ChunkSummary],
    function_name: &str,
    prefetched_caller_count: Option<usize>,
) -> FunctionHints

Core implementation — accepts pre-loaded graph and test chunks.

Use this when processing multiple functions to avoid loading the graph N times (e.g., scout, which processes 10+ functions).