Sync only filled empty spots and spots it had filled itself, so anyone
dragged in by hand stayed forever — pressing Sync for a new week swapped
some photos and left others, depending on how each spot got filled.
Hand placements are now stamped with the plan they were made for. Sync
keeps the ones made for the plan it is loading (a sub dragged in this
week survives a re-sync) and replaces or clears the rest. The last
synced plan is saved so placements made after a restart stamp right.
Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>