By: Michael Lynch <git@mtlynch.io>
Unexport uploads' proof-carrying Processable types ProcessableImage/ProcessableVideo and their constructors had no production callers outside uploads once ProcessImage/ProcessVideo became the package's only entry points; test files can't use an in-package export_test.go idiom here since check-go-test-packages requires an external _test package, so the uploads tests now exercise validation and processing through ProcessImage/ProcessVideo directly instead of the constructors.