The CSS change in 39575a0 added `display: flex` to the lightbox dialog
unconditionally, which overrode the browser's default `display: none`
for closed dialogs. This made the invisible lightbox overlay intercept
all clicks on the page.
Move flexbox properties to the `&[open]` selector so they only apply
when the dialog is actually open.
Also fix typo: `innerHtml` → `innerHTML` (capital H).
Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>
Remove data-action from the sanitizer allowlist to disallow injection
of potentially malicious Stimulus actions in user-provided
content. The lightbox controller now uses imageTarget callbacks to
handle clicks on image links.
Also add the file name as a caption in the light box, and fix the
caption color for dark mode visibility.