Add touch/mobile support for wish list drag and drop

[Copilot]

The wish list reordering relied solely on the HTML5 Drag & Drop API, which has no touch support, making reordering impossible on mobile devices.

Changes

• Touch event handlers added to each wish list item in renderWishList():
  • touchstart — captures source item ID, applies dragging class
  • touchmove (passive: false) — suppresses scroll, uses elementFromPoint (with transient visibility hide) to detect drop target, efficiently tracks previously highlighted item to avoid per-frame querySelectorAll
  • touchend — resolves final drop target and executes the same reorder logic as the mouse drop handler

let touchDragOverItem: HTMLElement | null = null;
el.addEventListener('touchstart', () => {
    this.dragSrcWishId = el.dataset.wishId!;
    el.classList.add('dragging');
}, { passive: false });
el.addEventListener('touchmove', (e) => {
    e.preventDefault();
    const touch = e.touches[0];
    el.style.visibility = 'hidden';
    const target = document.elementFromPoint(touch.clientX, touch.clientY);
    el.style.visibility = '';
    const targetItem = target?.closest<HTMLElement>('.wish-item') ?? null;
    if (targetItem !== touchDragOverItem) {
        touchDragOverItem?.classList.remove('drag-over');
        touchDragOverItem = targetItem !== el ? targetItem : null;
        touchDragOverItem?.classList.add('drag-over');
    }
}, { passive: false });

Mouse drag and drop is unchanged.

Original prompt

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This section details on the original issue you should resolve

<issue_title>Wish list drag and drop on mobile</issue_title>
<issue_description>The wish list items drag and drop on mobile does not currently work</issue_description>

Comments on the Issue (you are @copilot in this section)

• Fixes Wish list drag and drop on mobile #28

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