feat: add mine and class filters to statistics page

app/templates/statistics.html

@@ -6,6 +6,20 @@
 <div class="container-fluid py-4">
     <h2 class="mb-4"><i class="bi bi-bar-chart"></i> 数据统计</h2>
 
+    <!-- 筛选工具栏 -->
+    <div class="card mb-4">
+        <div class="card-body">
+            <div class="d-flex flex-wrap gap-3 align-items-center">
+                <button class="btn btn-primary btn-sm" id="mineFilterBtn" onclick="toggleMineFilter()">
+                    <i class="bi bi-person"></i> 我的
+                </button>
+                <select class="form-select form-select-sm" style="width:auto; min-width:120px;" id="classFilter" onchange="loadStatistics()">
+                    <option value="">全部班级</option>
+                </select>
+            </div>
+        </div>
+    </div>
+
     <!-- 顶部统计卡片 -->
     <div class="row mb-4">
         <div class="col-md-4">
@@ -131,12 +145,43 @@
 {% block extra_js %}
 <script>
 let severityChart, levelChart, classStudentChart, classProblemChart, problemNameChart;
+let mineFilterActive = false;
+
+function toggleMineFilter() {
+    mineFilterActive = !mineFilterActive;
+    const btn = document.getElementById('mineFilterBtn');
+    if (mineFilterActive) {
+        btn.classList.add('active');
+    } else {
+        btn.classList.remove('active');
+    }
+    loadStatistics();
+}
 
 async function loadStatistics() {
     try {
-        const resp = await fetch('/api/statistics/students');
+        const params = new URLSearchParams();
+        if (mineFilterActive) params.set('mine', 'true');
+        const classId = document.getElementById('classFilter').value;
+        if (classId) params.set('class_id', classId);
+
+        const resp = await fetch('/api/statistics/students?' + params.toString());
         const data = await resp.json();
 
+        // 填充班级筛选器
+        const classSelect = document.getElementById('classFilter');
+        if (classSelect.options.length <= 1) {
+            for (const c of data.classes || []) {
+                const opt = document.createElement('option');
+                opt.value = c.id;
+                opt.textContent = c.name;
+                classSelect.appendChild(opt);
+            }
+        }
+        if (classId) {
+            classSelect.value = classId;
+        }
+
         // 更新顶部卡片
         document.getElementById('totalStudents').textContent = data.total_students || 0;
         document.getElementById('totalProblems').textContent = data.total_problems || 0;