m.replace events no longer appear as their own "* text" line — the original row gets m.new_content and an (edited) marker. Media rows carry a [Image]/[Video]/[Audio]/[File] prefix and the JSON export includes mediaUrl; the UI notes attachments aren't included. Unit-tested. Fixes #50 Fixes #81 Co-Authored-By: Claude Opus 5 <noreply@anthropic.com> Claude-Session: https://claude.ai/code/session_01PPmy3tPq869XDW4njjVaKA