chore(runtime): snapshot the LIVE darwin soul runtime (el-sdk) into git

Verbatim capture of ~/el-sdk/el_runtime.{c,h} — the un-versioned source the live
macOS soul (:7770, 765760B) is actually built from. Captured so the data-integrity
fixes that exist ONLY in this file are no longer one rm away from gone with no history.

Contains (vs origin/main): the UAF fix (engram_node_full uses el_strdup_persist —
the hallucinated/lost-saves root cause; 27 sites vs 19) and the response-truncation
fix (max(strlen,_tl_fs_read_len) binary-safe reads).

DIVERGES BOTH WAYS: this snapshot LACKS main's newer engram_wm_*, engram_load_merge,
http_serve_async (diff is deletion-heavy as a result) and still lacks the atomic
engram_save (temp+fsync+rename) fix. DO NOT merge over main — reconcile by porting
the two fixes above forward onto main.

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

lang/el-compiler/runtime/el_runtime.h

@@ -176,7 +176,6 @@ el_val_t  http_set_handler(el_val_t name);
  * existing handlers (e.g. products/web/server.el): it dispatches with
  * (method, path, body), hardcodes 200 OK, and auto-detects content type. */
 el_val_t  http_serve_v2(el_val_t port, el_val_t handler);
-void      http_serve_async(el_val_t port, el_val_t handler);
 el_val_t  http_set_handler_v2(el_val_t name);
 
 /* Build an HTTP response envelope. `headers_json` should be a JSON object
@@ -639,12 +638,6 @@ el_val_t  engram_list_layers_json(void);
  * no nodes promoted to working memory. */
 el_val_t  engram_compile_layered_json(el_val_t intent, el_val_t depth);
 
-/* ── Working memory ──────────────────────────────────────────────────────────*/
-el_val_t  engram_wm_count(void);
-el_val_t  engram_wm_avg_weight(void);
-el_val_t  engram_wm_top_json(el_val_t n);
-el_val_t  engram_load_merge(el_val_t path);
-
 /* ── LLM (Anthropic API client) ─────────────────────────────────────────────
  * All functions call https://api.anthropic.com/v1/messages with the API key
  * from env ANTHROPIC_API_KEY. Default model when empty: claude-sonnet-4-5. */