Development-signed builds now opt into the Production CloudKit
environment via com.apple.developer.icloud-container-environment,
driven by a CLOUDKIT_ENV build setting. A new Debug-CKDev configuration
and "Yattee (CloudKit Dev)" scheme switch to the Development
environment for schema work.
The DEV badge and banner in iCloud settings now reflect the actual
environment (YatteeCloudKitEnvironment Info.plist key) instead of
#if DEBUG, and the sync engine logs the environment at startup.
Scheme-level build entries bypass the pbxproj target-dependency
platformFilter, so tvOS archives tried to build the iOS-only
ShareExtension and failed with "No profiles for *.ShareExtension".
The extension is still built on iOS via the Yattee target's
platform-filtered dependency and embed phase, matching how
YatteeTopShelf is wired for tvOS.
