Release v0.51.321 — Release KK (Phase 3 light: load renderable transcript tails, #3790) (#3798)

Phase-3-light. #3790 (@ai-ag2026): expand cold-load transcript window to ~msg_limit renderable rows so tool-heavy sessions don't open showing 1-2 messages. Codex CORE fix: explicit expand_renderable flag (cold-load only; Load-earlier keeps raw cap). Also fixed a recurring CI timing flake (git-parallel test → deterministic Barrier). Full suite 8228, Codex SAFE, Opus SHIP, CI 11/11. Co-authored-by: ai-ag2026 <ai-ag2026@users.noreply.github.com>

tests/test_issue3162_ensure_messages_loaded.py

@@ -16,8 +16,9 @@ SESSIONS_JS = (REPO / "static" / "sessions.js").read_text(encoding="utf-8")
 def _ensure_messages_loaded_body() -> str:
     start = SESSIONS_JS.index("async function _ensureMessagesLoaded")
     # Window widened (#3326 added reload-width-hint handling inside this function,
-    # pushing the carry-forward reassignment further down).
-    return SESSIONS_JS[start: start + 2600]
+    # pushing the carry-forward reassignment further down; #3790 added the
+    # cold-load expand_renderable param + comment, pushing it further still).
+    return SESSIONS_JS[start: start + 3000]
 
 
 def test_ensure_messages_loaded_declares_msgs_with_let():