Add an adjustable split between the video area and the timeline in mobile History view

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Describe what you are trying to accomplish and why in non technical terms**

On mobile devices, the History / Recording viewer can be difficult to use, especially with wide or ultra-wide camera aspect ratios.

The fixed layout means:

• some cameras appear too small when the timeline is visible
• there can be wasted space / black bars depending on aspect ratio
• users may want more room for the video at some moments and more room for the timeline at others
• using zoom alone is not enough because the real need is to rebalance space between the player and the timeline

Describe the solution you'd like

Add an adjustable split between the video area and the timeline in mobile History view.

Expected behavior:

• In mobile portrait layout, allow the divider between the video player and timeline to be dragged up or down
• Dragging the divider up gives more space to the timeline
• Dragging the divider down gives more space to the video
• The video should remain fit within its available bounds by default
• Zooming should then happen within the resized video area rather than being responsible for resizing the whole layout

This would let users choose the best balance depending on whether they are:

• closely inspecting footage
• scrubbing through time
• reviewing ultra-wide camera recordings

Describe alternatives you've considered

A fixed fit/fill toggle or pure zoom-based approach does not solve the layout issue as well, because the main problem is the amount of screen space allocated to the player versus the timeline.

Additional context

This would particularly improve usability on phones for wide-aspect cameras, while keeping the timeline accessible instead of forcing a fullscreen-only workflow.