fix: show unread counts as badges in the narrow-screen channel list

The dropdown already rendered a .sidebar-unread-badge element, but the
styling rule was scoped to .channel-sidebar-item, so on narrow screens the
count fell back to plain text in the row's own colour. Extend the selector
to .channel-selector-item so both views share one badge style.

Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>

app/static/css/style.css

@@ -118,7 +118,9 @@ main {
     white-space: nowrap;
 }
 
-.channel-sidebar-item .sidebar-unread-badge {
+/* Same badge in the sidebar (wide) and the navbar dropdown (narrow) */
+.channel-sidebar-item .sidebar-unread-badge,
+.channel-selector-item .sidebar-unread-badge {
     background-color: var(--sender-color);
     color: white;
     border-radius: 10px;

docs/whatsnew.md

@@ -10,6 +10,10 @@ For deep technical notes, see [architecture.md](architecture.md). For the full g
 
 ## Unreleased
 
+### Fixes
+
+- **Unread counts stand out in the channel list on a phone.** On a wide screen, a channel with unread messages shows the count in a blue badge next to its name. On a narrow screen the channel list is a drop-down from the top bar, and there the same number was drawn in plain text, the same colour and size as everything else in the row — easy to read as part of the timestamp and easy to miss entirely. It is now the same blue badge as on a wide screen.
+
 ---
 
 ## 2.4.1 — 2026-07-31