The old Tests/oAITests/oAITests.swift + root Package.swift/Sources/
were a swift package init stub that @testable imported a fake empty
oAI module, completely disconnected from the real ~31K-line app
(built only via oAI.xcodeproj). Running `swift test` there would
have silently "passed" while testing nothing.
oAITests is a proper Unit Testing Bundle target added via Xcode's
target editor, wired into the app's scheme (TestAction references
oAITests.xctest). Verified with `xcodebuild test` before and after
removing the dead scaffold.
First phase of the test-suite rollout plan (peaceful-baking-kurzweil).