self-review 2026-07-22: persist canonical snapshot on write routes; newest-first tie-break in node listings

Durability: the 2026-07-21 fix stopped read routes writing the canonical
snapshot but left no save on ANY write path — every mutation lived in RAM
until a manual POST /api/save. Observed live: two restarts reverted the
store to a 17h-old snapshot, destroying same-day writes. persist_canonical()
now runs after node/edge create, knowledge capture, forget, strengthen, and
load-merge. ISE telemetry excluded deliberately (48h-pruned, loss-tolerant,
~2/min; snapshotting 28MB per heartbeat is waste).

Listing order: scan routes sort by salience with store-order ties, so
equal-salience telemetry (all ISEs are 0.3) returned OLDEST first — a
limited /api/nodes query silently returned a stale window, and a 41h-old
heartbeat series read as a live outage during this review. Ties now break
newest-first by created_at.

lang/releases/v1.0.0-20260501/el_runtime.c

@@ -6958,14 +6958,24 @@ el_val_t engram_search(el_val_t query, el_val_t limit) {
     return lst;
 }
 
-/* Sort node indices by salience desc (small N, insertion sort is fine). */
+/* Sort node indices by salience desc, tie-break created_at desc (newest
+ * first). The tie-break matters for telemetry: InternalStateEvent nodes all
+ * share salience 0.3, so before this the listing routes returned them in
+ * store order — OLDEST first — and any limited query (/api/nodes?...&limit=N)
+ * silently returned a stale window. A 41-hour-old heartbeat series read as a
+ * live outage during the 2026-07-22 self-review. Newest-first ties make
+ * limited scans return the recent window consumers actually want.
+ * (Small N, insertion sort is fine.) */
 static void engram_sort_indices_by_salience(int64_t* arr, int64_t n,
                                              const EngramNode* nodes) {
     for (int64_t i = 1; i < n; i++) {
         int64_t key = arr[i];
         double  ks  = nodes[key].salience;
+        int64_t kc  = nodes[key].created_at;
         int64_t j = i - 1;
-        while (j >= 0 && nodes[arr[j]].salience < ks) {
+        while (j >= 0 && (nodes[arr[j]].salience < ks ||
+                          (nodes[arr[j]].salience == ks &&
+                           nodes[arr[j]].created_at < kc))) {
             arr[j + 1] = arr[j];
             j--;
         }