all: support hiding subconvo output

Some of it is systematically noisy.
diff --git a/webui/src/web-components/sketch-timeline-message.ts b/webui/src/web-components/sketch-timeline-message.ts
index b148203..f28b1a3 100644
--- a/webui/src/web-components/sketch-timeline-message.ts
+++ b/webui/src/web-components/sketch-timeline-message.ts
@@ -1090,11 +1090,11 @@
     pointer-events: none;
     transition: opacity 0.3s ease, transform 0.3s ease;
   }
-  
+
   .floating-message.success {
     background-color: rgba(40, 167, 69, 0.9);
   }
-  
+
   .floating-message.error {
     background-color: rgba(220, 53, 69, 0.9);
   }