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, 23 insertions, 0 deletions

diff --git a/apps/web/app/reader/settings/_components/appearance-settings.tsx b/apps/web/app/reader/settings/_components/appearance-settings.tsx
index 6c04f00..508051f 100644
--- a/apps/web/app/reader/settings/_components/appearance-settings.tsx
+++ b/apps/web/app/reader/settings/_components/appearance-settings.tsx
@@ -31,6 +31,10 @@ export function AppearanceSettings() {
   )
   const fontSize = useUserInterfaceStore((state) => state.fontSize)
   const setFontSize = useUserInterfaceStore((state) => state.setFontSize)
+  const contentFont = useUserInterfaceStore((state) => state.contentFont)
+  const setContentFont = useUserInterfaceStore(
+    (state) => state.setContentFont
+  )
   const timeDisplayFormat = useUserInterfaceStore(
     (state) => state.timeDisplayFormat
   )
@@ -155,6 +159,25 @@ export function AppearanceSettings() {
         </select>
       </div>
       <div className="mb-6">
+        <h3 className="mb-2 text-text-primary">content font</h3>
+        <p className="mb-3 text-text-dim">
+          controls the typeface used for article content
+        </p>
+        <select
+          value={contentFont}
+          onChange={(event) =>
+            setContentFont(
+              event.target.value as "sans-serif" | "serif" | "monospace"
+            )
+          }
+          className="border border-border bg-background-primary px-3 py-2 text-text-primary outline-none focus:border-text-dim"
+        >
+          <option value="sans-serif">sans-serif</option>
+          <option value="serif">serif</option>
+          <option value="monospace">monospace</option>
+        </select>
+      </div>
+      <div className="mb-6">
         <h3 className="mb-2 text-text-primary">time display</h3>
         <p className="mb-3 text-text-dim">
           choose between relative timestamps (e.g. &ldquo;2h ago&rdquo;) or