Add OpenVSX namespace verification check to publisher trust dialog

[azmkercso]

Summary

Query OpenVSX native API for real namespace verification status and display it in the extension trust dialog and gallery UI.

Changes

• ExtensionGalleryService: Added enrichOpenVsxVerificationStatus() that queries GET https://open-vsx.org/api/{namespace} for each publisher. Called from getExtensions() and query() so all consumers receive correct publisherDomain.verified data.

• Trust dialog (extensionManagementService):

  • Verified OpenVSX publishers now show the verified badge
  • Unverified publishers show an additional note: "Unverified namespaces on Open VSX can be claimed by anyone. Extensions from unverified publishers may not be from who you expect."
  • "Learn More" points to https://github.com/eclipse-openvsx/openvsx/wiki/Namespace-Access

• Gallery UI now correctly displays publisher verification status from OpenVSX.

Testing

• Dev-built and deployed to SageMaker Studio
• Verified trust dialog shows correct status for verified and unverified publishers
• Patch applies cleanly to all active branches (main, 1.0, 1.1, 1.2)