🎨 Palette: Add aria-current to active thread selection

.Jules/palette.md

@@ -1 +1,5 @@
 ## 2025-05-24 - Accessibility improvements in Toast component\n**Learning:** The Toast component used an icon-only button without an ARIA label. Added an aria-label with the translation 'Fermer', matching other close buttons in the app.\n**Action:** When adding close buttons, ensure they have proper aria-labels in French ('Fermer') to match the app's language.
+
+## 2024-06-25 - Sidebar list navigation accessibility
+**Learning:** Found that list-style navigation items (like the `ThreadSidebar`) used conditional background colors to indicate active states (`bg-[var(--color-accent-soft)]`), but completely lacked programmatic indicators for screen readers. This pattern is likely present in other custom sidebar lists.
+**Action:** Always add `aria-current="true"` (or `"page"` if it's a full page navigation) alongside visual "active" states in list selections to ensure state is announced to screen readers.

apps/web/src/components/chat/ThreadSidebar.tsx

@@ -30,6 +30,7 @@ export function ThreadSidebar({ rows, selected, onSelect, error, creating, busy,
             <li key={a.uuid}>
               <button
                 type="button"
+                aria-current={on ? 'true' : undefined}
                 class={cn(
                   'flex w-full items-start gap-2 rounded-xl py-2.5 text-left transition',
                   depth > 0 ? 'pl-7 pr-3' : 'px-3',
@@ -71,6 +72,7 @@ export function TeamSidebar({ rows, selected, onSelect, error, loading }: Props
             <li key={a.uuid}>
               <button
                 type="button"
+                aria-current={on ? 'true' : undefined}
                 class={cn(
                   'flex w-full flex-col rounded-xl py-2.5 text-left transition',
                   depth > 0 ? 'pl-7 pr-3' : 'px-3',