Allow user to change aspect ratio

### 📝 Description of the feature

As a SAF developer, I want to have the option to overwrite the visualization ratio of VISOR

### Acceptance Criteria

Set a different visualization ratio. Start VISOR. The viewer has the new vis. ratio.

### 💵 Business Value

_No response_

### 🔗 Useful links and references

_No response_

Start by locating where VISOR initializes the visualization and sets the current visualization ratio. Run VISOR to observe the existing viewer behavior, then verify that a user-provided ratio is applied when the viewer starts and that the resulting visualization uses the new ratio.

Rédigé par le modèle d'indexation à partir du texte de l'issue.