fix(a11y): add alt text to images for better accessibility

[huangkevin-apr]

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What have you changed?

Summary

This PR fixes accessibility violations by adding descriptive alt attributes to all images that were missing them.

Problem

When running IBM Accessibility Checker (Version 4.0.9) on the homepage, the IBM Equal Access Accessibility Checker identified QR-code images without alt text, which creates barriers for users relying on screen readers.

Why is this important?
When an image contains important information, providing a text alternative makes the same information accessible through assistive technologies, such as a Braille display. When an image is decorative or redundant, providing correct markup allows assistive technologies to ignore or not repeat the information.

Solution

Added meaningful alt text to images in both English (index.md) and Chinese (index.zh-CN.md) documentation
Updated the QrCode component to accept an alt prop and pass it to the underlying <img> element
Used descriptive alt text that conveys the purpose/content of each image:

• "Formily Form Builder" / "Formily 表单设计器"
• "Formily Core" / "Formily 内核"
• "Formily Community QR Code" / "Formily 社区二维码"

Testing

• Verified alt text appears correctly in the rendered HTML
• Confirmed IBM Equal Access Checker no longer reports violations for these images

Fix Before:

Fix After:

Impact

This change improves accessibility compliance and ensures all users, including those using assistive technologies, can understand the content and purpose of images on the site.

• The patch submitted in this PR was generated by A11YRepair, an automated Web Accessibility repair tool that I developed to address common accessibility violations in web applications. The generated fixes were manually reviewed and validated before submission.