Function build_ceo_entries 

pub fn build_ceo_entries(
    pack: &mut Pack,
    schema: &Schema,
    entries: &[CeoEntryData],
) -> Result<Vec<ContainerPath>>

Build CEO entries (armour, career, traits, loc) from structured input data.

This is the core logic for the BuildCeoEntries command, extracted to keep the background thread function manageable and to help the compiler optimize.