Running kolibri-format --write during the a11y remediation pass also fixed
pre-existing formatting violations in three kolibri-build files: node: protocol
prefixes on require() calls and a missing trailing comma.

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

…g elements

Adds alt="" to decorative images (coach prompts logo, channel thumbnails,
mobile header logo, slideshow slide image, app error bird) and rewrites
AppError.vue's img element to multi-line style to accommodate the attribute.

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

… focus management

Rewrites SafeHtmlImage to open Lightbox on Enter/Space keydown as well as click,
adds tabindex and role so the image is keyboard-reachable, and updates Lightbox
to accept and render arbitrary slot content. Updates the Lightbox spec to cover
the new keyboard interaction paths.

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

…ents

Addresses vuejs-accessibility/click-events-have-key-events,
no-static-element-interactions, and interactive-supports-focus violations:

- Adds role="presentation" to non-semantic wrapper divs used only for event
  delegation (Backdrop, CoreMenu, CoreSnackbar, SideNav, SidePanelModals,
  DragSortWidget, EpubRendererIndex, PerseusRendererIndex, OnboardingStepBase,
  CompletionModal) so the linter does not expect keyboard handlers on them.
- Converts AttemptLogList answer-history items from <a> to <div> with
  tabindex and aria-labelledby so keyboard users can reach them without
  using an anchor element without an href.
- Adds keyboard handlers (Enter/Space, Home/End, Up/Down) to
  QuestionDetailLearnerList so screen-keyboard users can navigate the listbox.
- Adds :aria-disabled + tabindex to PDFSideBar tabs instead of conditional
  tabindex=-1.
- Wires QTISandboxPage editor textarea aria-label and adds keyboard handlers
  to the item list.
- Converts FacilityAdminCredentialsForm from @keydown.enter to @submit.prevent.

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

…media captions

- Adds :title with a translated accessible label to the iframe in BloomPub,
  Html5App, and CustomContentRenderer viewers.
- Adds @focus/@blur to MediaPlayerTranscript so hovering state tracks keyboard
  focus (mouse-events-have-key-events).
- Wraps video sources in MediaPlayerIndex inside a <template v-for> to allow
  the <track> caption element to be a sibling (media-has-caption).
- Removes redundant explicit role="region" from SearchFiltersPanel (the
  enclosing element already provides that landmark implicitly).

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

…th form controls

Addresses label-has-for and related labeling violations:

- PicturePasswordOption: adds a unique id/for pair so the label is
  programmatically associated with its checkbox.
- SearchBox: adds role="search" to the wrapper and rewrites the visually-hidden
  label to use a KSR span associated with the input via for/id.
- DeviceSettingsPage: replaces <label> with <span> for visual-only fieldset
  headings that are not associated with any input.
- SelectFacilityPage/SelectFacilityForm: replaces <label for="select-address-button">
  with <span> since the target is a button, not an input.
- ImportCsvPage/Init.vue: reorders label before input so the association is
  unambiguous, and wraps both in a proper <label> element.

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>