Group @testable imports at the bottom, per public/rules-swift's swiftformat. A
behavior-preserving import-ordering reformat across 252 files (mostly tests).
--trailingclosures was deliberately not adopted (cosmetic, and swiftformat flags
it as caution-worthy).
The compact-syntax name class * - nameClass now parses as anyName except
the subtracted class (the model already had anyNameExcept). ns:* - name
would need an nsName-except model case and is left as a refinement.
Part of #79
