fix: ESLint errors and Prettier formatting

ESLint errors:
- usePresenceUpdater: remove redundant `const userId` inside handlePageHide
  that shadowed the outer declaration (no-shadow)
- RoomViewHeader: prefix unused encryptedRoom with _ (no-unused-vars)

Prettier: reformat 14 files to match project style

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

src/app/features/settings/notifications/Notifications.tsx

@@ -88,8 +88,14 @@ function NotificationPresets() {
               }}
             >
               <span style={{ fontSize: toRem(24) }}>{preset.emoji}</span>
-              <Text size="T300" style={{ fontWeight: 600 }}>{preset.label}</Text>
-              <Text size="T200" priority="300" style={{ textAlign: 'center', maxWidth: toRem(120) }}>
+              <Text size="T300" style={{ fontWeight: 600 }}>
+                {preset.label}
+              </Text>
+              <Text
+                size="T200"
+                priority="300"
+                style={{ textAlign: 'center', maxWidth: toRem(120) }}
+              >
                 {preset.description}
               </Text>
             </button>