chore: update to serene v5.4.3

BD103 · BD103 · commit e87671d9b968 · 2025-10-13T14:45:16.000-04:00
diff --git a/themes/serene b/themes/serene
@@ -1 +1 @@
-Subproject commit ba8bf3ca3cb5b19be5b2e34b0457a243309790e7
+Subproject commit 8491d732b588b353abc7f177bd13035775bd3a85
