The hand-written adapters wrote for a rollback to 3.2.3: a subset of
each page in the slots that build reads (no ellipses, view-cone or
circle agents, Miks, firearms, lineup graph or ability visibility) and
the whole page in JSON mirrors 3.2.3 ignores. Desktop users run 4.6.3
now, and 4.6.3 ignores those mirrors too. Rolled back, it opened pages
missing all of that, and its next save dropped the mirrors for good.
Folders lost role and game mode icons the same way.

Pages, placed agents, placed abilities and folders now write the very
bytes 4.6.3 writes. Every type in a page already exists in 4.6.3, so
nothing needs a mirror. Reading still prefers any mirror present, so
libraries saved by earlier cloud builds load whole.

The rollback tests decode with 4.6.3's own adapters, copied from the
release tag. Five fail against the old writer. The Windows upgrade
and rollback gate now starts from the 4.6.3 installer, not 3.2.3.

Co-Authored-By: Claude Opus 5.5 (1M context) <noreply@anthropic.com>