[Remote rendering 4.6] Viewport resize in REMOTE mode

### 📝 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_

Comece rastreando o observer de redimensionamento do canvas do frontend e a janela de renderização no lado do servidor, o interactor e o trigger de redimensionamento do widget de orientação no modo REMOTE. Verifique o comportamento existente de render-coalescing para eventos de redimensionamento rápidos e, em seguida, confirme que o redimensionamento preenche o canvas sem distorção e mantém o widget de orientação proporcional.

Escrita pelo modelo de indexação a partir do texto da issue.