Stage B proof: add per-VM consumed term to stadium_conserved -- FABRIC-3.6.md task 2.7

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

src/starkernel/vm/kernel_hermes.c

@@ -151,6 +151,7 @@ int sk_hermes_alloc(VMUuid vm_id, SkHermesMessage **out_msg) {
     memset(&sk_hermes_msgs[slot], 0, sizeof(SkHermesMessage));
     sk_hermes_msgs[slot].in_use      = 1;
     sk_hermes_msgs[slot].stadium_cell = (int32_t)cell;
+    sk_hermes_msgs[slot].owner        = vm_id;
     *out_msg = &sk_hermes_msgs[slot];
 
     /* Task 2.4: the one site where held/pulled increment -- only reached
@@ -222,6 +223,7 @@ int sk_hermes_decay(SkHermesMessage *msg) {
      * pays for it). SXXXVII.3: decay's delta is exact and in hand here. */
     sk_hermes_consumed += before - after;
     sk_hermes_held     -= before - after;
+    stadium_consumed_record(msg->owner, before - after);
     sk_hermes_audit();
 
     return 0;