Design-only planning artifact for #791. Traces the wipe mechanism
(install.sh:199 rsync --delete gated by PRESERVE_PATHS denylist) and
specifies the ratified (b)+(a)+(d) fix: framework-owned manifest allow-list
with fail-safe unknown=>operator default and manifest-scoped prune, a
transactional pre-update snapshot with mosaic restore, and a projection-only
mosaic fleet regen recovery path. No implementation changes.
Refs #791
Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>
