[Bug]: Camera zoom speed inverted/unstable on Safari with trackpad gestures
### What happened?

Safari (and possibly other non-Chromium browsers) exhibit incorrect zoom speed behavior with trackpad pinch-to-zoom when adjusting camera options. When setting lower zoom speeds, the camera paradoxically zooms **faster** and becomes unstable.

## Reproduction
1. Open Safari
2. Visit [Camera Options Demo](https://examples.tldraw.com/camera-options/full?preserveFocus=true)
3. Find the "Zoom Speed" control in the demo interface
4. Set value to `0.5` 
5. Try zooming using trackpad pinch gesture
  *(Note: May also affect scroll wheel zoom, but untested)*


https://github.com/user-attachments/assets/4ee128ff-50bb-441f-a50c-663e70f7dd79


## Behavior
### Expected
- Zoom should be 2x *slower* than default (matching Chrome)
- Motion should remain smooth throughout zoom

### Actual
#### Safari
- ~2x **faster** zoom than default
- Choppy/unstable motion
- Zoom sometimes resets to start position

*Note*: After noticing the inverse relationship, I tried setting `Zoom Speed` to `2` to attempt slowing it down by 50%. While this partially works (zoom is slower), after each zoom gesture completes, the view snaps back to the original zoom level (1).

#### Chrome
- Correctly shows 2x slower zoom
- Motion remains smooth
- Zoom level persists after gesture

## Environment
- macOS Sequoia 15.1 (24B83), reproduced on Sonoma
- Safari latest
- May affect other non-Chromium browsers

Really interested in understanding TLDraw's camera system better and potentially contributing a fix. Happy to pair on this or take pointers toward relevant codebase sections for investigation :)

### Where did this happen?

The developer package

### Contact Details

alp@hey.com

### Code of Conduct

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