Add information about how the clipboard/dataobject changes in .NET 10

[adegeo]

Summary

• Design a plan to document these changes.
• Write a new article to help people migrate.
• Migrate code to external files.
• Add VB code.
• Update existing articles that reference the clipboard or dataobject.
• Remove the committed plan files.

Fixes #2113

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📄 File	🔗 Preview link
.github/copilot-instructions.md	.github/copilot-instructions
.github/instructions/EditPass.instructions.md	.github/instructions/EditPass.instructions
.github/instructions/Plans.ClipboardWork.instructions.md	.github/instructions/Plans.ClipboardWork.instructions
.github/instructions/Snippets.Migrate.instructions.md	.github/instructions/Snippets.Migrate.instructions
.github/instructions/Snippets.Upgrade.instructions.md	.github/instructions/Snippets.Upgrade.instructions
.github/projects/clipboard/clipboard-dataobject-net10-changes.md	.github/projects/clipboard/clipboard-dataobject-net10-changes
.github/projects/clipboard/style-copilot-section-instructions.md	.github/projects/clipboard/style-copilot-section-instructions
.github/projects/clipboard/temp-clipboard-articles.md	.github/projects/clipboard/temp-clipboard-articles
AGENTS.md	AGENTS
dotnet-desktop-guide/winforms/advanced/drag-and-drop-operations-and-clipboard-support.md	dotnet-desktop-guide/winforms/advanced/drag-and-drop-operations-and-clipboard-support
dotnet-desktop-guide/winforms/advanced/how-to-add-data-to-the-clipboard.md	dotnet-desktop-guide/winforms/advanced/how-to-add-data-to-the-clipboard
dotnet-desktop-guide/winforms/migration/clipboard-dataobject-net10.md	dotnet-desktop-guide/winforms/migration/clipboard-dataobject-net10