pub fn load_units(
project_file: &Path,
active_configuration: Option<&str>,
) -> Result<Option<Units>, String>Expand description
Load units.json beside project_file, applying the active hardware-build
overlay if one is declared.
Ok(None) = the file is absent. That is degraded, not fatal (PLAN ยง3.1):
units being missing breaks display, not the machine, so the caller reports it
loudly and carries on rather than refusing to boot.