Clearer warnings when deleting a group

• ✓ Safer trust story for anyone cleaning up group structure

Removing a group is a bigger deal than it looks, so we spell it out: the dialog warns you clearly, and fact cards are unlinked as part of the delete so relationships stay consistent.

• Stronger warning copy before a group is removed

• Automatic unlinking of fact cards from the group being deleted

• Fewer orphaned or confusing group memberships after cleanup