java/v0.2.0

Changed

• Breaking: Move runtime configuration to Client.builder(database) and startup to Client.start(), which returns an AutoCloseable RunHandle for stop(), stopAndCancel(), and runtime queue/periodic controls. Workers is now a handler registry supplied through .workers(registry); .worker(type, handler) supports inline registration. Move subscriptions and event types to Client, allowing subscriptions before startup. A client allows one active run and can restart after shutdown completes. PR #1555.