fn read_bls_entry_for_deployment(
sysroot: &Sysroot,
deployment: &Deployment,
) -> Result<Option<String>>Expand description
Read the BLS entry file content for a deployment from /boot/loader/entries/.
Returns Ok(Some(content)) if the entry is found, Ok(None) if no matching
entry exists, or Err if there’s an I/O error.
We match by checking the options line for the deployment’s ostree path
(which includes the stateroot, bootcsum, and bootserial).