v0.2.9-beta

What's Changed

• chore: Bump version to 0.2.9-beta (4e14f47)
• fix: update Skeleton example to use non-obsolete APIs (bda71ca)
• fix: resolve all nullability warnings across codebase (28457bb)
• docs: add message publisher and React viewer roadmap (d256aa9)

Full Changelog: v0.2.8-beta...v0.2.9-beta