Compaction overhaul (#5186)

Co-authored-by: Douwe Osinga <douwe@squareup.com>
Co-authored-by: David Katz <dkatz@squareup.com>
Co-authored-by: Alex Hancock <alexhancock@block.xyz>

ui/desktop/src/hooks/useChatEngine.ts

@@ -340,6 +340,7 @@ export const useChatEngine = ({
           role: 'user',
           created: Date.now(),
           content: [],
+          metadata: { userVisible: true, agentVisible: true },
         };
 
         const notification = 'Interrupted by the user to make a correction';