hpc status: surface accounting fields for completed PJM jobs

[ultimatile]

Summary

Extend the hpc status <id> detail rendering (added in #5) to PJM clusters.
Currently only Slurm has a detail_cmd / parse_detail override, so PJM
jobs always fall back to the prior single-line Job <id>: <state> display.

Background

#5 added per-scheduler accounting display via Scheduler.detail_cmd /
Scheduler.parse_detail, returning a JobDetail(state, exit_code, elapsed, max_rss, req_mem) dataclass.
Slurm fetches it via sacct -P.
PJM was deferred at the time.

Proposal

Implement PJM equivalents using whatever accounting source PJM exposes
(typical candidates: pjstat -E, pjstat -X, the per-job log under
~/.pjm/).
Map the available fields onto the existing JobDetail shape; leave
unsupported fields as the empty string so the CLI's "field or -" rendering
still works.

Out of scope

• Changes to the Slurm detail path or the polling path.
• Adding new fields to JobDetail.