Prepare supervision 0.2.8 release

[lucas-fochesatto]

Description

Prepare supervision 0.2.8 so consumers can use additive selection while editing annotations and avoid idle rendering work for still images.

Type of Change

• Refactor or maintenance
• Documentation or example update

Validation

• Documentation updated for the release version
• npm run verify (3,410 tests passed)
• npm run package:tarball
• npm run package:tarball:smoke
• npm run package:publish:dry-run

Notes For Reviewers

Since v0.2.7:

• Render still images on change instead of every animation frame #142: render still images on change instead of every animation frame.
• Preserve multi-selection while editing annotations #143: preserve multi-selection while editing and support host-driven selection groups.

Backward-compatible patch under the repository's 0.x release policy. After merge, run the protected Publish npm package workflow from main with the latest tag.