Function assemble_context 

pub fn assemble_context(
    db: &Database,
    brain_dir: &Path,
    prompt: &str,
    opts: &ContextOptions,
) -> Result<ContextBundle>

Assemble a graph-aware context bundle for an agent prompt.

brain_dir is the .brain directory (for loading graph.mmap). When the mmap file is missing or the mmap feature is disabled, expansion is skipped and only ranked seeds are packed.

Errors

Propagates FTS / database errors from the seed query.