docs(persisted-scope): document protocol-asset feature

[MihirMohapatra]

Summary

Adds missing README docs for the protocol-asset feature in auri-plugin-persisted-scope.

Changes

• Add a dedicated protocol-asset section to the plugin README.
• Explain default behavior (filesystem scope persistence only).
• Explain when to enable protocol-asset for �sset:// runtime scope mutations.
• Add Cargo feature example.
• Clarify that asset scope state is stored separately and restored on next start.

Closes #918.

[github-actions]

Package Changes Through 8d51375

There are 4 changes which include global-shortcut with patch, global-shortcut-js with patch, positioner with patch, positioner-js with patch

Planned Package Versions

The following package releases are the planned based on the context of changes in this pull request.

package	current	next
api-example	2.0.43	2.0.44
api-example-js	2.0.39	2.0.40
global-shortcut	2.3.1	2.3.2
global-shortcut-js	2.3.1	2.3.2
positioner	2.3.1	2.3.2
positioner-js	2.3.1	2.3.2

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