선생님 대시보드에 학년 필터 칩 추가

출석자/미출석자 필터처럼 학년 전체/1학년/2학년/3학년 칩을 추가해서
선택한 학년만 볼 수 있게 함. 상태 필터와 조합해서 같이 적용됨.

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

lib/function/teacher_attendance_controller.dart

@@ -26,6 +26,7 @@ class TeacherAttendanceController extends ChangeNotifier {
   bool _isLoading = true;
   bool _isRefreshing = false; // 새로고침 버튼 클릭 시 잠깐 도는 표시용
   String _filterType = "ALL"; // "ALL", "CHECKED_IN", "ABSENT"
+  String _gradeFilter = "ALL"; // "ALL", "1", "2", "3"
   bool _disposed = false;
 
   // ----------------------------------------------------------------
@@ -34,6 +35,7 @@ class TeacherAttendanceController extends ChangeNotifier {
   bool get isLoading => _isLoading;
   bool get isRefreshing => _isRefreshing;
   String get filterType => _filterType;
+  String get gradeFilter => _gradeFilter;
   String? get attendanceTime => _attendanceTime;
   String? get globalPermissionUntil => _globalPermissionUntil;
 
@@ -214,6 +216,12 @@ class TeacherAttendanceController extends ChangeNotifier {
     _safeNotify();
   }
 
+  /// 🏫 학년 필터. "ALL"이면 전체, "1"/"2"/"3"이면 그 학년만 보이게 한다.
+  void setGradeFilter(String grade) {
+    _gradeFilter = grade;
+    _safeNotify();
+  }
+
   // ----------------------------------------------------------------
   // 파생 로직 (출석 상태 계산)
   // ----------------------------------------------------------------
@@ -301,13 +309,17 @@ class TeacherAttendanceController extends ChangeNotifier {
   }
 
   List<Map<String, dynamic>> get filteredStudents {
-    final all = combinedStudentStatus;
+    var result = combinedStudentStatus;
     if (_filterType == "CHECKED_IN") {
-      return all.where((s) => s['isAttendanceComplete'] == true).toList();
+      result = result.where((s) => s['isAttendanceComplete'] == true).toList();
     } else if (_filterType == "ABSENT") {
-      return all.where((s) => s['isAttendanceComplete'] == false).toList();
+      result = result.where((s) => s['isAttendanceComplete'] == false).toList();
     }
-    return all;
+    if (_gradeFilter != "ALL") {
+      final int? grade = int.tryParse(_gradeFilter);
+      result = result.where((s) => s['grade'] == grade).toList();
+    }
+    return result;
   }
 
   /// 🏫 [학년별 카테고리] filteredStudents를 학년(1~3학년) 순서로 묶는다.

lib/ui/teacher_attendance_page.dart

@@ -706,20 +706,23 @@ class _TeacherAttendancePageState extends State<TeacherAttendancePage> {
   Widget _buildFilterChips() {
     return Padding(
       padding: const EdgeInsets.symmetric(vertical: 8, horizontal: 16),
-      child: Row(
+      child: Column(
+        crossAxisAlignment: CrossAxisAlignment.start,
+        children: [
+          Wrap(
+            spacing: 8,
+            runSpacing: 8,
             children: [
               FilterChip(
                 label: const Text("전체"),
                 selected: _controller.filterType == "ALL",
                 onSelected: (_) => _controller.setFilter("ALL"),
               ),
-          const SizedBox(width: 8),
               FilterChip(
                 label: const Text("🟢 출석자"),
                 selected: _controller.filterType == "CHECKED_IN",
                 onSelected: (_) => _controller.setFilter("CHECKED_IN"),
               ),
-          const SizedBox(width: 8),
               FilterChip(
                 label: const Text("🔴 미출석자"),
                 selected: _controller.filterType == "ABSENT",
@@ -727,6 +730,35 @@ class _TeacherAttendancePageState extends State<TeacherAttendancePage> {
               ),
             ],
           ),
+          const SizedBox(height: 8),
+          Wrap(
+            spacing: 8,
+            runSpacing: 8,
+            children: [
+              ChoiceChip(
+                label: const Text("학년 전체"),
+                selected: _controller.gradeFilter == "ALL",
+                onSelected: (_) => _controller.setGradeFilter("ALL"),
+              ),
+              ChoiceChip(
+                label: const Text("1학년"),
+                selected: _controller.gradeFilter == "1",
+                onSelected: (_) => _controller.setGradeFilter("1"),
+              ),
+              ChoiceChip(
+                label: const Text("2학년"),
+                selected: _controller.gradeFilter == "2",
+                onSelected: (_) => _controller.setGradeFilter("2"),
+              ),
+              ChoiceChip(
+                label: const Text("3학년"),
+                selected: _controller.gradeFilter == "3",
+                onSelected: (_) => _controller.setGradeFilter("3"),
+              ),
+            ],
+          ),
+        ],
+      ),
     );
   }
 }