Friends scene rebuilt:
- 3 tabs: الأصدقاء (all), الطلبات (pending), متصلين (online)
- Search players by username (🔍 button → input + results)
- Send friend request with + button (success feedback)
- Accept/reject pending requests (✓/✕ buttons)
- Remove friend (with confirm dialog)
- Challenge online friend (⚔️ → navigates to game select)
- View profile button
- Online dot indicator on avatars
- Empty states with helpful CTAs

API updated:
- New action: search — finds players by username (ilike)
- Returns id, username, display_name, avatar_url, level, is_online

UI polish:
- Tab system with active state
- Card-based friend list with actions
- Animations and haptic on interactions
Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>