[APPS] Viewport configuration and real-device rendering

Problem:

Current preview mode for mobile and web apps is very limited. Reviewers cannot easily verify how a mobile/web app renders across different device sizes, orientations, OS behaviors or browser engines. This limits confidence in visual/functional bug triage and can lead to inaccurate issues.

Feature requests:

• Add controls to set preview screen size, orientation (portrait/landscape), target platform (iOS/Android/Web) and browser (Chrome/Firefox/Safari) when reviewing mobile and web apps so previews match real-device rendering.

Goals

• Let reviewers simulate target devices and browsers so reported issues reflect real-world rendering.

• Make these settings easy to change, persist, and share with teammates.