Add accessibility improvements to data tables

## Description

Data tables across the app need accessibility improvements to support screen readers and keyboard navigation. ## Tasks

• [ ] Add \` \` elements to all tables describing their content
• [ ] Add \`scope=\"col\"\` to \` \` elements
• [ ] Add \`aria-label\` to icon-only action buttons (edit, delete, view)
• [ ] Ensure proper keyboard focus order in table rows
• [ ] Add \`aria-sort\` attributes to sortable columns ## Pages with Tables
• Items list (\`/c/[slug]/items\`)
• Customers list