feat(scheduler-sim-decision-parity): relocate resource accounting to core-level (task 1.1)

Relocates sched_account_jobs()/sched_charge_account()/sched_uncharge_account()/
sched_update_account()/sched_update_res_accounts()/sched_commit_job_alloc()
from xce_scheduler_t* to xce_sched_core_t*, mirroring the sched_resolve_job_picker()
precedent, so the simulation driver can call the same accounting service the
normal-mode driver already uses. Pure signature relocation -- every body
reference was already sched->core.*, no logic change. Updates the 3 real call
sites (driver.c's normal-mode round, scheduler.c's sched_begin_session and
sched_commit_decision) and 7 existing tests' link-satisfying stub signatures.

Adds test_resource_accounting.c proving Requirement 1.4: the relocated
accounting produces identical resInUse/sharedInUse output whether called
against a core embedded in xce_scheduler_t or xce_sched_sim_driver_t.

43/44 scheduler tests pass; the 1 failure is pre-existing bug-1560
(unrelated recording.c sandbox-permission ordering issue).

Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com>

src/scheduler/testsuite/test_admin_request.c

@@ -178,9 +178,9 @@ int plugin_end_session(void* arg)
     return 0;
 }
 
-int sched_account_jobs(xce_scheduler_t* sched)
+int sched_account_jobs(xce_sched_core_t* core)
 {
-    (void)sched;
+    (void)core;
     return 0;
 }