Summary

Add a branded Microsoft logo icon to all HVE Core VS Code extension variants so they display a recognizable icon on the Visual Studio Marketplace.

Changes Required

• Add extension/icon.png (128×128+ PNG, Microsoft four-square logo)
• Add "icon": "icon.png" to extension/templates/package.template.json
• Add !icon.png to extension/.vscodeignore

Acceptance Criteria

• All extension variants display the icon on the Marketplace
• npm run lint:all passes
• Icon is valid PNG, minimum 128×128 pixels