release: ship MasterSelects 1.6.0

[Sportinger]

Summary

• Adds draggable timeline clip keyframe markers for faster keyframe timing edits.
• Fixes native 3D video plane rendering through the shared scene camera/render path.
• Cleans warning noise and stale debug artifacts across editor UI, preview, export, project storage, native helper, playback, and tests.
• Bumps app version to 1.6.0 and updates the in-app changelog.

Verification

• npm run build
• npm run lint
• npm run test (104 files, 2137 tests)

[cloudflare-workers-and-pages]

Deploying masterselects with    Cloudflare Pages

Latest commit:	30d4e56
Status:	✅  Deploy successful!
Preview URL:	https://bb065601.masterselects.pages.dev
Branch Preview URL:	https://staging.masterselects.pages.dev

View logs