fix(accessibility): add descriptive alt text

[remo-lab]

Summary

This PR addresses missing or generic alt text in images across Phoenix components.
Several elements previously had empty or non‑descriptive alt attributes, which reduced accessibility for screen reader users and failed WCAG 2.1 Level A (1.1.1 Non‑text Content).
By adding meaningful alt text, this PR improves inclusivity, user experience, and compliance with accessibility standards.

Changes Made

Files Updated:
- packages/phoenix-ng/projects/phoenix-app/src/app/home/home.component.html

• packages/phoenix-ng/projects/phoenix-ui-components/lib/components/ui-menu/io-options/io-options-dialog/io-options-dialog.component.html

Details:

• Home component (7 images):
  • Replaced empty alt on logo with "Phoenix Event Display Logo".
  • Replaced generic "Card image cap" with descriptive alt text for each card (e.g., "ATLAS detector visualization", "CMS detector visualization", "TrackML visualization").
• IO Options dialog (7 images):
  • Added descriptive alt text for icons (e.g., "OBJ file format icon", "GLTF file format icon", "Save scene icon").

Impact

• 14 insertions (new descriptive alt text).
• 9 deletions (removed empty/generic alt text).
• 15 images now have proper accessibility labels.

Result

• All images now have descriptive alt text.
• Screen reader users receive meaningful context.
• Meets WCAG 2.1 Level A requirements.
• Improves accessibility, SEO, and overall user experience.

Screen.Recording.2025-12-31.140437.mp4

[remo-lab]

Hi @EdwardMoyse ,
This PR fixes accessibility issues by adding descriptive alt text to 15 images across the Home component and IO Options dialog.
This improves screen reader support and brings the project closer to WCAG 2.1 Level A compliance.
Could you please review when you have a chance? Your feedback will help ensure the changes align with project standards. Thanks!

[EdwardMoyse]

Thank you very much @remo-lab - this PR is very much appreciated.