- Add role="alert" to the global error banner and the inline add-form
error message so screen readers announce errors immediately on render
- Add aria-label to all three add-form inputs (key / value / TTL) so
every form control has an accessible name (was flagged as unlabelled)
- Add aria-expanded={expanded === entry.key} to each entry toggle button
so AT announces collapsed/expanded state on activation
Closes#902
Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>