Added #

• Asynchronous parsing surface: ActivityParser.parseAsync, parseBytesAsync, and parseStream optionally offload work to isolates for smoother UIs and streaming IO.
• ActivityFiles facade providing ergonomic load, convert, and edit helpers tailored for app integrations.
• RawActivityBuilder for incremental creation of activities.
• Asset-backed integration tests cover ActivityFiles.load, detectFormat, and conversion flows with real GPX/TCX/FIT fixtures.

Changed #

• GPX, TCX, and FIT parsers emit structured diagnostics instead of raw strings.
• Converter, CLI, documentation, examples, and tests now surface diagnostics in output flows.
• README/example now highlight the high-level facade and builder workflows.
• Added facade-focused regression tests covering format detection and builder seeding.

Deprecated #

• ActivityParseResult.warnings remains available but now forwards to the new structured diagnostics; it is marked deprecated to encourage migration.
• ActivityConverter.convert still accepts the warnings parameter, which is deprecated in favor of the richer diagnostics sink.

• pub.dev score fix.

• Fix README.

• Handle FIT compressed timestamp headers and ensure unknown message types advance the reader instead of hanging.
• Add ActivityParser.parseBytes, broaden ActivityConverter.convert input support, and let the CLI operate on raw FIT binaries without manual base64.
• Document the new FIT workflow and add regression coverage for compressed headers.

• Upgrade dependencies and SDK.
• Add example/main.dart illustrating a minimal GPX round-trip.

• Initial release of activity_files with GPX/TCX parsing, editing, validation, and encoding utilities plus a conversion/validation CLI scaffold.