soul: engram-store wiring (soul client path) + elc-fold source fixes

- soul.el/memory.el: ENGRAM_STORE-gated store boot/checkpoint (client path) + fix a
  latent memory.el segfault (engram_save returns Int, was str_eq'd as a pointer).
- sessions.el/safety.el/chat.el: fix malformed El constructs that hung the elc fold
  (unterminated string literals, block-expression, undefined distill_transcript).

memory.el

@@ -109,8 +109,22 @@ fn mem_consolidate() -> String {
 }
 
 fn mem_save(path: String) -> Void {
-    let save_result: String = engram_save(path)
-    if str_eq(save_result, "") {
+    // ENGRAM_STORE on: the durable path is a checkpoint of the resident graph into
+    // the paged store (persists learned hebb + activation-formed edges via the WAL).
+    // The JSON engram_save stays available as an explicit export elsewhere; here the
+    // store is authoritative, so we checkpoint instead of writing the snapshot.
+    let store_flag: String = env("ENGRAM_STORE")
+    if str_eq(store_flag, "1") || str_eq(store_flag, "on") || str_eq(store_flag, "true") {
+        let ck: Int = engram_store_checkpoint()
+        if ck == 0 {
+            println("[memory] mem_save: engram_store_checkpoint returned 0 — checkpoint may have failed")
+        }
+        return
+    }
+    // engram_save returns Int 1/0 (ok/fail), not a String — checking it as a
+    // String (str_eq(save_result, "")) dereferences a tagged int and segfaults.
+    let save_result: Int = engram_save(path)
+    if save_result == 0 {
         println("[memory] mem_save: engram_save failed for " + path + " — snapshot may be incomplete")
     }
 }