HAR-9797 - feat: added initial support for high contrast mode

[chittolinag]

Added support for high contrast mode.

• When enabled, the toolbar and the editor borders should have maximum contrast.
• Users can enable/disable it by calling setHighContrastMode on the main SuperDoc instance.

How to enable:

const config = {
  // ...
  onReady: (event) => {
    event.superdoc.setHighContrastMode(true);
  }
  // ...
}

const editor = new SuperDoc(config);
// Or at any point (after the editor is ready)
editor.setHighContrastMode(true);

This function can be called programatically at any point.

UI changes:

• Toolbar items (hover state, dropdowns).
• Editor borders.

[harbournick]

one quick comment on the package-lock that looks to be unintended

[harbournick]

Let's remove any changes in this lock file unless strictly necessary to prevent any potential issues with install (we've had issues with unintentional changes in lock files)

[chittolinag]

@artem-harbour @harbournick The idea I came up with for now is to keep two composables, one for superdoc, one for supereditor. We do have to change colors on both packages, but given the timeline I couldn't really figure out a way to keep a same shared state - but I'm super open to suggestions in case you know a better approach to do so!

[harbournick]

LGTM