[Remote rendering 4.6] Viewport resize in REMOTE mode #31

📝 Description of the feature

Keep the server-side render window in step with the canvas size so the stream isn't stretched and the orientation widget stays proportional. A resize trigger updates the render window, interactor, and orientation widge; the frontend observes canvas resize and fires it.

Note: rapid resize events during a drag shouldn't trigger a render per event. Whether that's handled by the existing render coalescing or its own rate-limiting is a call for this story; not a settled requirement.

Acceptance Criteria

After a resize the stream fills the canvas without distortion and the orientation widget stays proportional.

💵 Business Value

No response

🔗 Useful links and references

No response