Add exact-equality Hermes ledger self-audit -- FABRIC-3.6.md task 2.6

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

src/starkernel/vm/kernel_hermes.c

@@ -48,6 +48,7 @@
 #include "starkernel/vm/kernel_hermes.h"
 #include "starkernel/vm/stadium.h"
 #include "starkernel/q48_16.h"
+#include "console.h"
 
 static SkHermesMessage sk_hermes_msgs[SK_HERMES_MSG_MAX];
 
@@ -66,6 +67,27 @@ void sk_hermes_ledger(uint64_t *held, uint64_t *pulled, uint64_t *returned, uint
     if (consumed) *consumed = sk_hermes_consumed;
 }
 
+int sk_hermes_audit_values(uint64_t held, uint64_t pulled, uint64_t returned, uint64_t consumed) {
+    /* Epsilon zero (SXXXVII.3): exact integer equality, no tolerance. */
+    return held == pulled - returned - consumed;
+}
+
+static uint64_t sk_hermes_audit_failures = 0;
+
+int sk_hermes_audit(void) {
+    int ok = sk_hermes_audit_values(sk_hermes_held, sk_hermes_pulled,
+                                    sk_hermes_returned, sk_hermes_consumed);
+    if (!ok) {
+        sk_hermes_audit_failures++;
+        console_println("Kernel-Hermes AUDIT FAILURE: held != pulled - returned - consumed");
+    }
+    return ok;
+}
+
+uint64_t sk_hermes_audit_failure_count(void) {
+    return sk_hermes_audit_failures;
+}
+
 static int sk_hermes_find_free_slot(void) {
     int i;
     for (i = 0; i < SK_HERMES_MSG_MAX; i++) {
@@ -135,6 +157,7 @@ int sk_hermes_alloc(VMUuid vm_id, SkHermesMessage **out_msg) {
      * once every refusal path above has already returned. */
     sk_hermes_held   += pulled;
     sk_hermes_pulled += pulled;
+    sk_hermes_audit();
 
     return 0;
 }
@@ -176,6 +199,7 @@ int sk_hermes_release(SkHermesMessage *msg) {
     if (rc == 0) {
         sk_hermes_held     -= remaining;
         sk_hermes_returned += remaining;
+        sk_hermes_audit();
     }
 
     memset(msg, 0, sizeof(*msg));
@@ -198,6 +222,7 @@ 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;
+    sk_hermes_audit();
 
     return 0;
 }