Native analytics API

AnalyticsDispatcher, DurableQueue, AnalyticsContext, QueueEntry, DecideUpload and AnalyticsSampled are portable C++ interfaces. FGraffityAnalyticsStore accepts directory, opaque partition and an optional host Upload callback. PauseUploads/Flush control bounded worker delivery. Host destination/schema mapping remains explicit; no remote endpoint/project key is selected by the SDK.