feat(studio): support preview panning with mouse and trackpad

[func25]

What

Add middle-mouse and trackpad panning to the Studio preview.

Why

These are the convenient and standard ways to move around the preview in many visualization platforms.

How

• Keep preview pan in the existing preview camera layer.
• Handle middle mouse drag through the existing pointer pan path.
• Handle two-finger pan through the preview wheel path.
• Keep pan clamped to the preview content surface, with a small overscroll margin so it does not hard-stop at the edge.

Test plan

How was this tested?

• Unit tests added/updated
• Manual testing performed
• Documentation updated (if applicable)

[miguel-heygen]

can you share a video testing it pls?

[func25]

Sure, here is the white scene test video, use midlde-mouse to move around:

Screen.Recording.2026-05-16.at.13.42.30.mov

[O1Anas]

Great feature @func25 ! Would you be open to adding trackpad two-finger panning support as well?

This would provide parity with tools like Remotion, where users can pan by dragging with two fingers on their trackpad. It's a common gesture on modern laptops and would make the preview navigation feel more complete.

[func25]

Added, thanks for the idea (I saw your recommendation in the zoom in/out GitHub issue also)

[O1Anas]

Thank you so much for the fast response & commit @func25 ! It would be great if we can also include some of these small features/bug fixes in this PR too (or else I'll file a new issue instead, what do you think?):

1. Mouse wheel/trackpad zoom focuses into the center – Currently, mouse wheel/trackpad zoom always zooms into the center of the composition. It should zoom into the mouse pointer's location for intuitive navigation.

2. Reset zoom button – Currently, double-clicking on the canvas resets zoom (undocumented/hidden). I Suggest adding a visible, consistent 'Reset Zoom' button.

3. Canvas border expands inward when zooming – The gray border of the canvas grows thicker and eats into the preview canvas. This was previously reported (see PR fix(studio): canvas border expands when zooming — switch from CSS zoom to transform scale #810) and is not fixed (PR was closed & not merged); the issue still happens in the current release and appears connected to CSS zoom vs. transform: scale.

Zoom screenshots:

When zoomed out:

When zoomed in:

[func25]

Let's file a new issue. This PR should only handle panning :)