v0.2.0 of fractalup_radar_flutter

Production observability SDK for Flutter with errors, logs, metrics, RUM, distributed tracing, privacy controls, and offline delivery. Changelog excerpt: - Added automatic Flutter and platform error capture. - Added structured logs, metrics, RUM, navigation, HTTP instrumentation, and W3C distributed tracing. - Added durable bounded delivery, payload sanitization, privacy controls, sampling, sessions, lifecycle events, and runtime/device context. - Added migration-compatible exception monitoring and mobile-agent APIs under the FractalUp namespace. - Added publication metadata, examples, validation tooling, and ELv2 licensing.