fix(a11y): FileWidget and RegistryImageWidget a11y improvements - backport

[Wagner3UB]

Backport of #7982 from Volto 19 to Volto 18, with an additional fix for the screen reader announcement when a file is already present.

Changes

• FileWidget: added role="button", aria-labelledby, and aria-describedby to the dropzone container for proper keyboard and screen reader support
• FileWidget: label is now aria-hidden with stopPropagation on click to prevent double file dialog opening
• FileWidget: hidden status span announces upload instructions, required state, and current filename to screen readers
• FileWidget: distinguishes between "open file browser" and "replace existing file" in the screen reader announcement depending on whether a file is already uploaded (improvement over the original v19 PR)
• FileWidget: aria-required and aria-invalid added to the file input
• FileWidget: download link now has a descriptive aria-label with the filename
• FileWidget: new fieldSet prop to correctly build the aria-labelledby reference
• RegistryImageWidget: updated editFile message to match new wording
• main.less: added padding-bottom: 1rem to .file-widget-dropzone
• locales: translated all new/updated strings across 65 languages

[read-the-docs-community]

Documentation build overview

📚 volto | 🛠️ Build #33560299 | 📁 Comparing f04e057 against latest (65547ad)

  🔍 Preview build  

106 files changed · + 1 added · ± 96 modified · - 9 deleted

+ Added

• development/add-ons/theme.html

± Modified

• genindex.html
• index.html
• blocks/block-style-wrapper.html
• blocks/settings.html
• client/future-improvements.html
• client/index.html
• client/misc.html
• client/quick-start.html
• conceptual-guides/add-ons.html
• configuration/environmentvariables.html
• and 86 more...

- Deleted

• deploying/subpath.html
• development/known-dev-watcher-issue.html
• development/shadowing.html
• reference/index.html
• reference/utilities.html
• reference/widgets.html
• theming/create-theme-add-on.html
• development/add-ons/test-add-ons-19.html
• development/add-ons/theme-add-on.html

[stevepiercy]

A sprinkling of MyST markup, and a concern to address.

This needs a technical review as well.

[stevepiercy]

Yay! msgids preserved. LGTM. Thank you!

[wesleybl]

I noticed that the text has changed since the PR on the main branch. I think that, for consistency and to facilitate future backports, the text should be the same. If that's the case, we need to update the text on the main branch.

[Wagner3UB]

I noticed that the text has changed since the PR on the main branch. I think that, for consistency and to facilitate future backports, the text should be the same. If that's the case, we need to update the text on the main branch.

@wesleybl You are right. But the problem isn't here, its in the 19 version: #8334

[Wagner3UB]

I noticed that the text has changed since the PR on the main branch. I think that, for consistency and to facilitate future backports, the text should be the same. If that's the case, we need to update the text on the main branch.

@wesleybl Here we are good to go. I did a fix on the main PR to be like this one. We can continue.