starkernel: item 4.2 -- Hermes native on the Stadium (complete)

Migrates Hermes's message/channel lifecycle onto the Stadium's unified
heat/capacity economy: MSG-ALLOC/FREE-NODE and CH-ALLOC/FREE-NODE now
route entirely through stadium_admit()/stadium_evict(), replacing the
old local free-list + independent heat-field mechanism. Eight
kernel-only STADIUM-* FORTH primitives (ADMIT, EVICT, RES@, RES-PULL,
RES-PUSH, HEAT@, HEAT!, WORD-HEAT), VM.stadium_vm_id threaded through
all three vm_core.c dispatch sites (replacing item 4.1's hardcoded
vm_uuid_hera()), and the stadium_owner[idx] fix so evict-credit lands
in the VM that actually admitted a patron, not whoever owned cell 0.

This session's own contribution, on top of that pre-existing
implementation: found and fixed two bugs blocking the item's own K≡1.0
conservation self-check (HERMES-K was reading 0, not 65536):

- Q.SLOT admission-heat fix (capsules/hermes/init.4th): MSG-SEND/
  CH-ACCEPT admitted with Q.1 (the entire fleet-wide "1.0" unit) per
  item, a leftover from before the Stadium migration when each
  message/channel had its own unconstrained heat field. Instantly
  drained the shared, finite reservoir.

- Reservoir floor for word-execution admission (stadium_words.c):
  stadium_word_dispatch() (item 4.1) pulls STADIUM_WORD_HEAT_QUANTUM on
  every word dispatch, not just first admission -- exhausts a VM's
  entire reservoir in ~32 dispatches, starving any application-level
  economy sharing that VM's reservoir before it gets a chance to pull
  anything. word_dispatch_pull() now clamps word-execution's own pulls
  to leave a Q48_ONE/3 floor (same fair-share figure COMMON-CH's own
  floor already uses); application-level pulls are unaffected.

- STADIUM-WORD-HEAT primitive + stadium_words_resident_heat(): the
  floor deliberately leaves word-execution residents holding real
  heat, invisible to HERMES-K's original formula (MSG+CH+reservoir,
  no term for word patrons). Adding this term closes K to exactly
  65536 on all three architectures.

Also rules on two open scope questions in FABRIC.md: MBR-ALLOC/
MBR-FREE-NODE stay off the Stadium (membership records have no heat
field, never did -- the acceptance bullet's inclusion of them was a
completeness gesture predating a check of the actual layout), and
records the effort number (12 implementation files, +759/-120 lines).

Verified: all three architectures boot clean, full self-test passes,
Stadium conservation closes exactly (resident_sum + reservoir =
Q48_ONE) at both the C/Stadium level and the FORTH-level HERMES-K
check.

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

src/starkernel/vm/bootstrap/sk_vm_bootstrap.c

@@ -271,6 +271,7 @@ int sk_vm_bootstrap_parity(ParityPacket *out) {
      * capsule_birth_baby() which never calls vm_init_with_host(). */
     capsule_vm_hooks_register();
     capsule_vm_registry_init(vm);  /* establishes [Hera] console prefix */
+    vm->stadium_vm_id = vm_uuid_hera(); /* item 4.2 */
     vm_physics_init(vm_uuid_hera()); /* Hera: the fleet's root, seeded Q48_ONE */
     capsule_run_log_init();
     register_mama_forth_words(vm); /* BIRTH KILL START STOP USE + capsule words */