games_services_watchos 0.0.1

watchOS implementation of the games_services plugin: Game Center leaderboards over GameKit, bridged with dart:ffi.

0.0.1

• Initial staged release: the watchOS implementation of games_services.
• Leaderboards only — sign-in, score submission, and reading entries. Achievements, saved games and the access point keep the platform interface's UnimplementedError defaults; GKGameCenterViewController and GKAccessPoint do not exist on watchOS, so there is nothing to present and no partial version worth shipping.
• Not yet verified end to end on a physical watch: GKLocalPlayer reports an authenticated player with an unresolved alias and GameKit then refuses loadEntries. See PORTING_REPORT.md.