feat: support node copying between `Chatflow` and `Workflow` apps

[lexmin0412]

Summary

The clipboardElements state can be shared across Chatflow and Workflow apps through localStorage now.

Fix https://github.com/langgenius/dify/pull/19708 Close https://github.com/langgenius/dify/issues/17566

Screenshots

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Checklist

[!IMPORTANT]
Please review the checklist below before submitting your pull request.

• [ ] This change requires a documentation update, included: Dify Document
• [x] I understand that this PR may be closed in case there was no previous discussion or issues. (This doesn't apply to typos!)
• [x] I've added a test for each change that was introduced, and I tried as much as possible to make a single atomic change.
• [x] I've updated the documentation accordingly.
• [x] I ran dev/reformat(backend) and cd web && npx lint-staged(frontend) to appease the lint gods

[crazywoola]

Ref https://github.com/langgenius/dify/pull/19821

[pennn778]

Can wait to use this function

[CrabSAMA]

Are there any new progress? This feature is very important to me. 🤕

[jzymx50]

stale PR but important to DX. pls make a move!

[lexmin0412]

It's strange why there has been no progress or any feedback for so long. I'm about to close this PR.