fix: increase tap target sizes for checkboxes and icon buttons on mobile

[jglopez]

Problem

Checkboxes and small icon buttons (e.g. delete row) are sized for mouse precision. On a touchscreen they're easy to mis-tap when items are tightly spaced.

Proposed solution

Ensure interactive elements meet the minimum 44×44pt touch target size (Apple HIG / WCAG 2.5.5). Use padding, min-h/min-w Tailwind utilities, or invisible hit-area wrappers.

Affected files

• src/components/ItemsTable.tsx — checkboxes and delete buttons per row

Acceptance criteria

• Checkboxes and icon buttons are comfortably tappable on a phone without zooming.
• Desktop visual layout is unchanged.