[Bug]: Auto-zoom frames the background instead of the video content when changing aspect ratio (16:9 to 1:1)

[claudionardin]

Describe the bug
When a project is recorded in a 16:9 aspect ratio but the canvas is set to 1:1 (Square) in the editor, the auto-zoom and panning logic calculates the frame based on the entire 1:1 canvas (including the padding/background) rather than the actual 16:9 video layer. This causes the camera to zoom partially into the empty background areas (top or bottom) instead of keeping the recorded video in focus.

To Reproduce

1. Record a screen in a 16:9 aspect ratio, intentionally clicking multiple times near the corners/edges of the screen.
2. Open the recorded video in the editor.
3. Change the project/canvas format to 1:1 (which adds background padding to the top and bottom).
4. Press play and observe the auto-zoom and pan behavior around the clicks.

Expected behavior
The zoom and pan logic should anchor its calculations strictly to the bounding box of the recorded video layer (+ padding). When zooming in, it should magnify the actual screen content, completely ignoring the extra background padding added by the 1:1 canvas.

Screenshots

[meiiie]

Added the bug label. This looks like the same zoom-transform path as PR #403, which is currently the focused fix candidate for the 16:9 video inside a 1:1 canvas case.

Keeping this open until that PR lands and the 16:9 -> 1:1 auto-zoom repro is retested.