fix(controller,apiserver,xcecli): expose job CPU peak and efficiency to the apiserver and xcecli (bug-1736)

The controller computed run usage (CPU time, memory, CPU peak and
efficiency, LSF bjobs -l definitions) but the capnp Job struct had no
field for it, so the job pushed to the apiserver never carried it, and
snapshots (the same struct) dropped it: a job restored from a checkpoint
lost its accumulated usage.

- controller.capnp: Job.runUsage @13 (JobRunusage); old entries decode
  with no run usage.
- apiserver: map run_usage into JobInfo; max_mem, avg_mem, used_mem,
  cpu_time, peak_cpu, peak_cpu_time, peak_cpu_duration, mem_efficiency,
  avg_cpu_efficiency, peak_cpu_efficiency become queryable columns.
- xcecli: -o fields MAX_MEM, AVG_MEM, MEM_EFFICIENCY, CPU_PEAK,
  CPU_PEAK_DURATION, CPU_EFFICIENCY, CPU_PEAK_EFFICIENCY (CPU_TIME now
  renders too), and a MEMORY USAGE / CPU USAGE block in jobs list -l.

Co-Authored-By: Claude Opus 5.5 (1M context) <noreply@anthropic.com>

src/schema/controller.capnp

@@ -338,6 +338,7 @@ struct Job $C.mapname("xce_job_t"){
   pendreason     @10: JobPendReason $C.mapname("pend_reasons");
   transientSince @11: UInt64 = 0 $C.mapname("transient_since");  # epoch seconds; set when job enters JOB_STAT_TRANSIENT
   exitInfo       @12: JobExitInfo $C.mapname("exit_info");  # bug-1867: null until the job's exit code is known
+  runUsage       @13: JobRunusage $C.mapname("run_usage");  # bug-1736: null until the first usage report; snapshot + apiserver
 }
 
 # bug-1867: job_exitinfo_t, so a checkpointed Job keeps its exit code. The