A `git filter-repo` pass on 2026-04-29 dropped 10 path patterns from history that were already deleted from HEAD (CMake/JUCE build output, generated PDF bifolds, an old GIF, an APK release artifact). Add them to .gitignore so they can't accidentally re-enter history via a forgetful `git add -A` or a tool that drops artifacts in-tree. Net reclaim from gc + filter: 1.4 GB → 845 MB (~40%). Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>