submit: JOB_TEMPLATE emits Slurm-form --output= / --error= directives for PJM jobs

[ultimatile]

Summary

JOB_TEMPLATE in src/hpc/job.py injects scheduler-bookkeeping
output and error directives in Slurm form
(--output=..., --error=...) for both Slurm and PJM jobs.
PJM (pjsub) uses -o <path> and -e <path> instead, so the
emitted lines are not valid PJM directives.

Repro

hpc.toml with [cluster] scheduler = "pjm", then
hpc submit "echo hi" and inspect the rendered job script
(uploaded under <workdir>/.hpc/runs/<run_id>/job.sh):

#PJM -L node=12
...
#PJM --output=/.../job-%j.out
#PJM --error=/.../job-%j.err

The last two lines are Slurm-style; PJM's pjsub does not honor
them. Job stdout / stderr therefore land at PJM's default
locations rather than under
<workdir>/.hpc/runs/<run_id>/job-<job_id>.out, which breaks
hpc job-output <run_id> (it reads from the hpc-tracked path).

Expected

For PJM, the bookkeeping lines should be emitted as #PJM -o <path>
and #PJM -e <path>, with the path / wildcard substitution
adjusted to PJM conventions
(%j is Slurm's; PJM uses %j in some configurations and the
job-id substitution differs across PJM versions — needs
investigation).

Notes

• This was identified during research for a separate issue but kept
  out of scope to keep that fix minimal.
• The fix likely needs a per-scheduler hook for emitting output /
  error directives, since the syntax and substitution conventions
  diverge.
• hpc job-output resolution
  (get_job_output in src/hpc/job.py) assumes the hpc-controlled
  path layout, so this needs to stay aligned with whatever PJM
  actually writes.