Samsung just announced its seventh-generation folding phones, and it finally retired the long and narrow Z Fold design that it had stuck with for far too long. The Z Flip is also getting an overdue upgrade to a full-size cover screen rather than the file folder shape of the past couple generations. After years of incremental upgrades and barely warmed-over designs, Samsung’s foldables are finally taking a leap forward with some bold choices — just be prepared to pay up for them.We knew the Fold ...