fix(artboard): prevent accidental duplicates when dragging placed cards

[Go2Engle]

Summary

Clicking and dragging a card already on the artboard could start a browser image drag. Dropping that image onto the artboard could upload it again and add an accidental duplicate. Placed cards now stay on the sheet when dragged, while clicking still opens the artwork preview and dropping external image files still adds artwork.

Type of change

• Feature
• Bug fix
• Refactor
• Documentation
• Infrastructure/CI

Technical details

• Cancel drag-start events from placed card buttons so their artwork cannot become an upload drag.
• Disable selection within placed cards to prevent selection while clicking and dragging.
• Update the feature reference and Cricut workflow guide with the card click behavior and external artwork drop workflow.

Testing performed

npm test
npm run build

All 188 tests passed, and the production build completed successfully.

Playwright browser validation confirmed that a mouse drag on a placed image was canceled, the card count remained unchanged, and the upload overlay did not appear. A normal click opened the artwork dialog. A simulated external PNG file drop displayed the upload overlay, added one card, and cleared the overlay afterward. After merging the latest main, browser checks reconfirmed canceled image drags and artwork clicks, and verified that right-button dragging over a card still pans the preview and stops on release.

Breaking changes

None.

Checklist

• The PR title follows Conventional Commits.
• I ran npm test and npm run build.
• I added or updated tests for behavior changes. (Validated the browser interactions with Playwright; no new automated test file.)
• I updated documentation for user-facing changes.
• I updated the README feature summary if this feature belongs on the website overview. (Not applicable to this bug fix.)
• I did not manually edit release versions or CHANGELOG.md.