sk_vm_parked_idle(): saved context + exactly its own IDLE frame.
capsule_vm_kill_refusal() is the single kill rule, shared by
capsule_vm_kill() and the KILL word: refuse SWITCHED_OUT mid-task, parked
with mail pending, or the VM running; allow parked-idle. capsule_vm_kill()
now unregisters the switch slot (G6).
Finding fixed: vm_registry_alloc() never initialized pending_reap (kmalloc
does not zero); C-b's reap_pending walks every participant, so garbage
reaped a healthy VM (seen live before any KILL). Now zeroed at alloc.
Probe (reverted): baseline KILL refused, slots 3->4->4 (FAIL, proves G6);
with Stage D dprobe parked idle, KILL dead, slots 3->4->3, PASS on amd64/
aarch64/riscv64. Acceptance: dict_hash unchanged, relay 3, idle growth 0.
Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
