feat(useDraggable): allowing calculations of bounds with fixed element

[linspw]

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• Read the Contributing Guidelines.
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• Check that there isn't already a PR that solves the problem the same way to avoid creating a duplicate.
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Description

The feature's idea is to be able to pass a fixed container for bounds calculations. This is especially useful when you have another calculation scale or when working with CSS Transforms (translation). This feature allows a calculation relative to the element you choose.

Additional context

There is a similar initiative in this PR #3219.

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🤖 Generated by Copilot at b1328a2

Add custom container option to useDraggable. This lets the user choose a different element than the document body as the reference for the draggable element's position and boundaries.

🤖 Generated by Copilot at b1328a2

• Add containerElement property to UseDraggableOptions interface to allow specifying a custom element for bounds calculation (link)
• Pass containerElement from options to useDraggable function (link)
• Use containerElement or target to get the bounding rectangle of the container element in useDraggable function (link)
• Adjust x and y values of pos object based on the relative position of the mouse pointer inside the container element (link)

[linspw]

@antfu , sorry to see this right on top of the merge, but maybe I need to make a little tweak to the move handler, I think it needs to consider bounds too

Maybe doing everything in PR is just better what do you think?

[linspw]

Just to register the adjustment can come later, it's not a matter of breaking anything.