feat: resolve 7 pre-ship QoL items

- Space/Shift+Space: page down/up in detail panel (80% scroll)
- Content font: sans-serif/serif/monospace selector in appearance
  settings, applied to article content in detail panel
- Accessibility: entry-list-item uses button instead of div, folder
  toggles have aria-expanded, shortcut keys have aria-labels
- Share notes: replaced window.prompt with proper modal dialog
  matching existing UI patterns
- Worker .env.example: template with all 10 environment variables
- Worker poisoned messages: archive unprocessable queue messages
  instead of leaving them stuck forever
- Worker pool Submit: check return value, reschedule dropped feeds
  30s into the future, log warnings for rejected submissions

1 files changed, 1 insertions, 0 deletions

diff --git a/apps/web/app/reader/_components/sidebar-content.tsx b/apps/web/app/reader/_components/sidebar-content.tsx
index e13926d..17d07bb 100644
--- a/apps/web/app/reader/_components/sidebar-content.tsx
+++ b/apps/web/app/reader/_components/sidebar-content.tsx
@@ -279,6 +279,7 @@ export function SidebarContent() {
             >
               <button
                 type="button"
+                aria-expanded={isExpanded}
                 onClick={() =>
                   toggleFolderExpansion(folder.folderIdentifier)
                 }