fix: support mobile drag gestures

[Found-L]

Summary

• replace mouse-only image and GIF resize handling with Pointer Events
• use pointer capture to keep resizing active when a touch or pointer moves outside the resize handle
• support touch drag selection in the table size picker while preserving desktop hover behavior
• prevent browser scrolling from interrupting resize and table selection gestures

Root cause

The image and GIF resize handles only listened for mouse events, and the table size picker relied on mouse hover and mouse down events. These interactions therefore did not work correctly on touch devices.

Video behavior

The current video extension no longer provides drag resize handles. Video width is adjusted through the existing S/M/L controls in the bubble menu, which are already usable on touch devices. This PR keeps that interaction unchanged.

Validation

• TypeScript type check
• lint for the modified files
• formatting check for the modified files
• library production build
• playground production build
• verified compatibility with the latest GIF size persistence changes from PR fix: preserve GIF size after reload #373

Closes #115

[vercel]

@Found-L is attempting to deploy a commit to the Gia Hung's projects Team on Vercel.

A member of the Team first needs to authorize it.