Improve widescreen layout to better use available horizontal space

[patrickrb]

Problem
The current layout leaves a large amount of unused horizontal space on widescreen displays, while the main waterfall and control areas remain constrained to a narrower central layout.

Proposed improvement

Implement a responsive widescreen design that better uses available horizontal real estate. The goal is to make the UI feel more balanced and intentional on large displays, rather than leaving large empty areas.

Ideas shown in the screenshot

• Extend the waterfall area horizontally on wider screens
• Reserve additional space for bandswitch and related controls
• Improve the overall composition so secondary panels can expand instead of remaining compact
• Keep the existing dark visual style and avoid cluttering the core operating controls

Acceptance criteria

• The layout adapts more effectively to widescreen resolutions
• Additional space is used for useful controls or content instead of remaining empty
• The waterfall remains readable and visually prominent
• The experience still works well on smaller screens

Screenshot