feat: Aether Drift UI polish — popout redesign, sidebar cleanup, status dot fix

- Redesign UserProfilePopout with glass material, viewport clamping, flow-based
  avatar layout, and subtle send-message button
- Server sidebar: downsize icons to 40px (matching prototype), remove nonfunctional
  Explore button, add separator before action buttons, replace Tooltip with native
  title, remove hover boxShadow artifacts
- Avatar status dot: fixed 12px size with semi-transparent border for universal
  cutout effect matching the design prototype
- MemberListToggleButton: distinct three-person icon (was duplicate of Add Friends)
- FriendsPage: fix Add Friend button contrast (dark text on mint background)
- ChannelSidebar: rename Nitro/Shop to Coming Soon placeholders

packages/web/src/components/ui/Avatar.tsx

@@ -69,12 +69,13 @@ export function Avatar({ src, name, size = 40, status, className = '', onClick,
       </div>
       {status && (
         <div
-          className={`absolute -bottom-0.5 -right-0.5 rounded-full border-[3px] border-surface-channel ${statusColors[status] ?? 'bg-status-offline'}`}
+          className={`absolute rounded-full ${statusColors[status] ?? 'bg-status-offline'}`}
           style={{
-            width: size * 0.35,
-            height: size * 0.35,
-            minWidth: 12,
-            minHeight: 12,
+            width: size <= 24 ? 10 : 12,
+            height: size <= 24 ? 10 : 12,
+            bottom: -2,
+            right: -2,
+            border: '3px solid rgba(22, 22, 40, 0.72)',
           }}
         />
       )}