* fix(registry): wait for background meta refresh before test reset
TestComputeMinimumScopeSet can start doBackgroundRefresh via Init() while
the next test's resetInit() mutates package-level globals the goroutine
still reads (e.g. remoteMetaURL / configuredBrand), causing data races under
-race in the coverage job.
Track the refresh goroutine with a WaitGroup and drain it at the start of
resetInit() in tests.