The /autocompact interactive dialog (with up/down arrow selection of compact window sizes and the "Long context that holds up" marketing copy) has been removed. Auto-compact window configuration is now done exclusively through settings.json (autoCompactWindow key) or the CLAUDE_CODE_AUTO_COMPACT_WINDOW environment variable.
Evidence
Removed dialog component vP1 and command registration aT7 from old version
Strings lifted out of the shipped bundle, so the claim above can be checked against them.