feat(engram): /api/sync route for soul daemon periodic pull; update ELP type headers

engram/dist/engram.c

@@ -23,6 +23,7 @@ el_val_t route_forget(el_val_t method, el_val_t path, el_val_t body);
 el_val_t route_save(el_val_t method, el_val_t path, el_val_t body);
 el_val_t route_load(el_val_t method, el_val_t path, el_val_t body);
 el_val_t route_health(el_val_t method, el_val_t path, el_val_t body);
+el_val_t route_sync(el_val_t method, el_val_t path, el_val_t body);
 el_val_t route_emit_ise(el_val_t method, el_val_t path, el_val_t body);
 el_val_t check_auth_ok(el_val_t method, el_val_t body);
 el_val_t handle_request(el_val_t method, el_val_t path, el_val_t body);
@@ -277,6 +278,21 @@ el_val_t route_health(el_val_t method, el_val_t path, el_val_t body) {
   return 0;
 }
 
+el_val_t route_sync(el_val_t method, el_val_t path, el_val_t body) {
+  el_val_t dir = env(EL_STR("ENGRAM_DATA_DIR"));
+  if (str_eq(dir, EL_STR(""))) {
+    dir = EL_STR("/tmp/engram");
+  }
+  el_val_t snap_path = el_str_concat(dir, EL_STR("/snapshot.json"));
+  engram_save(snap_path);
+  el_val_t snap = fs_read(snap_path);
+  if (str_eq(snap, EL_STR(""))) {
+    return EL_STR("{\"nodes\":[],\"edges\":[]}");
+  }
+  return snap;
+  return 0;
+}
+
 el_val_t route_emit_ise(el_val_t method, el_val_t path, el_val_t body) {
   el_val_t content = json_get_string(body, EL_STR("content"));
   if (str_eq(content, EL_STR(""))) {
@@ -364,6 +380,9 @@ el_val_t handle_request(el_val_t method, el_val_t path, el_val_t body) {
   if (str_eq(method, EL_STR("POST")) && (str_eq(clean, EL_STR("/api/load")) || str_eq(clean, EL_STR("/load")))) {
     return route_load(method, path, body);
   }
+  if (str_eq(method, EL_STR("GET")) && str_eq(clean, EL_STR("/api/sync"))) {
+    return route_sync(method, path, body);
+  }
   return el_str_concat(el_str_concat(EL_STR("{\"error\":\"not found\",\"path\":\""), clean), EL_STR("\"}"));
   return 0;
 }

engram/src/server.el

@@ -206,6 +206,28 @@ fn route_health(method: String, path: String, body: String) -> String {
     "{\"status\":\"ok\",\"engine\":\"engram-runtime-native\"}"
 }
 
+// route_sync — return a snapshot of non-ISE/non-Working nodes for the soul daemon
+// to merge into its in-process graph via engram_load_merge.
+//
+// The soul calls GET /api/sync every SOUL_REFRESH_MS (default 10 min) to pull
+// new Knowledge/Memory/BacklogItem nodes from the authoritative HTTP Engram into
+// its in-process working store. Previously this returned 404 "not found", causing
+// the soul to write the error JSON to a temp file and attempt an empty merge.
+//
+// Strategy: save the current snapshot to disk, read it back, return the full
+// snapshot JSON. The soul's engram_load_merge handles large files gracefully
+// (it skips nodes already present by ID). Auth-exempt: same-host internal call.
+// (2026-06-27 self-review: added this route to fix silent 10-min sync failures)
+fn route_sync(method: String, path: String, body: String) -> String {
+    let dir: String = env("ENGRAM_DATA_DIR")
+    if str_eq(dir, "") { let dir = "/tmp/engram" }
+    let snap_path: String = dir + "/snapshot.json"
+    engram_save(snap_path)
+    let snap: String = fs_read(snap_path)
+    if str_eq(snap, "") { return "{\"nodes\":[],\"edges\":[]}" }
+    return snap
+}
+
 // route_emit_ise — write an InternalStateEvent node from the soul daemon.
 //
 // Endpoint: POST /api/neuron/state-events
@@ -330,6 +352,11 @@ fn handle_request(method: String, path: String, body: String) -> String {
         return route_load(method, path, body)
     }
 
+    // Sync — soul daemon periodic pull of non-ISE knowledge into in-process graph
+    if str_eq(method, "GET") && str_eq(clean, "/api/sync") {
+        return route_sync(method, path, body)
+    }
+
     "{\"error\":\"not found\",\"path\":\"" + clean + "\"}"
 }