Function build_task_context 

pub fn build_task_context(
    root: &Path,
    goal: &str,
    files: &[String],
    symbols: &[String],
    budget: Option<usize>,
    hook: bool,
) -> Result<TaskContextArtifact>

Build the complete task artifact: scorer + beads + hindsight enrichment for the pack, then the SAME-scorer task delta against the ledger. hook keeps the whole focus within the §37 1500-token cap (the delta gets what the pack leaves); an explicit budget caps the total; the default gives the delta its own task_delta slice.