fix(modal): close rollout and async lifecycle gaps

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>

assets/js/core/modal-runtime.js

@@ -342,11 +342,12 @@
       },
     };
 
-    session.flight = cacheable
+    var flight = cacheable
       ? cache.acquire(cacheKey, request, acquireOptions)
       : { promise: request(), release: function () {} };
+    session.flight = flight;
 
-    return session.flight.promise.then(function (result) {
+    return flight.promise.then(function (result) {
       if (!session.closed && active === session) renderResult(session, result);
       return session.shell;
     }).catch(function (error) {
@@ -354,8 +355,12 @@
       if (!aborted && !session.closed && active === session) renderError(session, error);
       return session.shell;
     }).then(function (shell) {
-      if (session.flight && typeof session.flight.release === "function") session.flight.release();
-      session.flight = null;
+      // A refresh/replacement may have installed a newer flight on this session.
+      // Only the owner of this promise may release and clear the slot.
+      if (session.flight === flight) {
+        if (flight && typeof flight.release === "function") flight.release();
+        session.flight = null;
+      }
       return shell;
     });
   }