선생님 호출 화면 이모티콘을 검정 아이콘으로 통일

위치 이모티콘(🏢🍴🧪 등)을 Material 아이콘으로, 랭킹 메달 이모티콘을
백품타 랭킹 화면과 같은 금/은/동 색 emoji_events 아이콘으로 교체.

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

lib/ui/teacher_call_screen.dart

@@ -239,8 +239,13 @@ class _TeacherCallScreenState extends State<TeacherCallScreen> {
     );
   }
 
+  static const List<Color> _medalColors = [
+    Color(0xFFC9A227), // 금
+    Color(0xFF9AA0A6), // 은
+    Color(0xFFB07A4B), // 동
+  ];
+
   Widget _buildRanking() {
-    final medals = ['🥇', '🥈', '🥉'];
     return Container(
       padding: const EdgeInsets.all(14),
       decoration: BoxDecoration(
@@ -272,7 +277,11 @@ class _TeacherCallScreenState extends State<TeacherCallScreen> {
               for (var i = 0; i < _controller.ranking.length; i++)
                 Column(
                   children: [
-                    Text(medals[i], style: const TextStyle(fontSize: 22)),
+                    Icon(
+                      Icons.emoji_events_rounded,
+                      color: _medalColors[i],
+                      size: 22,
+                    ),
                     Text(
                       _controller.ranking[i]['teacherName'] ?? '',
                       style: const TextStyle(fontWeight: FontWeight.bold),
@@ -436,14 +445,26 @@ class _TeacherCallScreenState extends State<TeacherCallScreen> {
                   ),
                 ),
                 const SizedBox(height: 2),
-                Text(
-                  '${kLocationIcons[location] ?? '📍'} $location',
-                  maxLines: 1,
-                  overflow: TextOverflow.ellipsis,
-                  style: TextStyle(
-                    fontSize: 11,
-                    color: isSelected ? Colors.white70 : Colors.grey[500],
-                  ),
+                Row(
+                  children: [
+                    Icon(
+                      kLocationIcons[location] ?? Icons.location_on_rounded,
+                      size: 12,
+                      color: isSelected ? Colors.white70 : Colors.grey[500],
+                    ),
+                    const SizedBox(width: 3),
+                    Expanded(
+                      child: Text(
+                        location,
+                        maxLines: 1,
+                        overflow: TextOverflow.ellipsis,
+                        style: TextStyle(
+                          fontSize: 11,
+                          color: isSelected ? Colors.white70 : Colors.grey[500],
+                        ),
+                      ),
+                    ),
+                  ],
                 ),
               ],
             ),