Full Workbench Lift

Completed

• Workspace trust disabled across all 5 workbench profiles (Mountain, Electron, Browser, BrowserProxy, index)
• Extensions directory created at Target/Static/Application/extensions
• xterm addons promoted to stable releases

Remaining

• SkyBridge editor/applyEdits routes to wrong command (applyThemeFromFile)
• Input box and quick-pick dialogs need proper VS Code UI
• SkyBridge installation timing (2s hardcoded delay — race condition risk)
• console.log in SkyBridge violates zero-console policy

See CHANGELOG.md