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).
A >> follow-annotation after a pattern (a foreign element name with
optional [ ... ] content) is skipped, chaining and combining with leading
annotations; neither carries schema semantics. Namespace declarations
inside annotations were already dropped by the annotation skipper, so the
RNC compact syntax is now fully covered.
