feat: 多班级版 v2.0 - Go后端重写 + 43轮代码审查

- 后端从 Python FastAPI 重写为 Go Gin（端口 56789）
- 多班级完全隔离
- 超级管理员独立登录
- 课代表作业管理、排行榜分项排行
- 角色加减分上下限可配置
- 家长改密功能（可开关）
- 周度/月度重置功能
- MySQL 5.7 兼容
- 43轮代码审查+全部修复
- Apache 2.0 许可证

frontend/parent/password.php

@@ -0,0 +1,106 @@
+<?php
+/**
+ * 多班级版班级管理系统 - 家长修改密码页
+ * 
+ * 开发者: Canglan
+ * 联系方式: admin@sea-studio.top
+ * 版权归属: Sea Network Technology Studio
+ * 许可证: Apache License 2.0
+ * 
+ * 版权所有 © Sea Network Technology Studio
+ */
+
+$page_title = '修改密码';
+require_once __DIR__ . '/../config.php';
+
+if (!isset($_SESSION['user_id']) || $_SESSION['user_type'] !== 'parent') {
+    header('Location: /index.php');
+    exit();
+}
+
+include __DIR__ . '/../includes/header.php';
+?>
+
+<div class="nav">
+    <a href="/parent/dashboard.php" class="nav-item">首页</a>
+    <a href="/parent/history.php" class="nav-item">历史记录</a>
+    <a href="/parent/attendance.php" class="nav-item">考勤记录</a>
+    <a href="/parent/password.php" class="nav-item active">修改密码</a>
+</div>
+
+<div class="container">
+    <div class="card">
+        <div class="card-title">修改密码</div>
+        <div id="featureDisabled" style="display:none;">
+            <p style="text-align:center;color:#999;padding:30px 0;">该功能暂未开放，请联系班主任启用"家长改密"功能开关。</p>
+        </div>
+        <form id="passwordForm" style="display:none;">
+            <div class="form-group">
+                <label>原密码 <span style="color:red;">*</span></label>
+                <input type="password" id="oldPassword" required>
+            </div>
+            <div class="form-group">
+                <label>新密码 <span style="color:red;">*</span></label>
+                <input type="password" id="newPassword" required>
+                <small>密码长度6-20位，需包含大写字母、小写字母、数字、特殊符号中的至少3种</small>
+            </div>
+            <div class="form-group">
+                <label>确认新密码 <span style="color:red;">*</span></label>
+                <input type="password" id="confirmPassword" required>
+            </div>
+            <button type="submit" class="btn btn-primary">确认修改</button>
+        </form>
+    </div>
+</div>
+
+<script>
+async function checkFeature() {
+    var res = await apiGet('/api/class/features');
+    if (res && res.success && res.data && res.data.features) {
+        var val = res.data.features.parent_password_change_enabled;
+        var enabled = val === 1 || val === '1' || val === true;
+        if (enabled) {
+            document.getElementById('passwordForm').style.display = '';
+        } else {
+            document.getElementById('featureDisabled').style.display = '';
+        }
+    } else {
+        document.getElementById('featureDisabled').style.display = '';
+    }
+}
+
+document.getElementById('passwordForm').addEventListener('submit', async (e) => {
+    e.preventDefault();
+    
+    var oldPassword = document.getElementById('oldPassword').value;
+    var newPassword = document.getElementById('newPassword').value;
+    var confirmPassword = document.getElementById('confirmPassword').value;
+    
+    if (newPassword !== confirmPassword) {
+        showToast('两次输入的新密码不一致', 'error');
+        return;
+    }
+    
+    if (newPassword.length < 6 || newPassword.length > 20) {
+        showToast('密码长度需为6-20位', 'error');
+        return;
+    }
+    
+    var res = await apiPost('/api/parent/password', {
+        old_password: oldPassword,
+        new_password: newPassword
+    });
+    
+    if (res && res.success) {
+        showToast('密码修改成功，请重新登录');
+        setTimeout(function() { logout(); }, 1500);
+    } else {
+        showToast(res && res.message ? res.message : '密码修改失败', 'error');
+    }
+});
+
+document.addEventListener('DOMContentLoaded', checkFeature);
+</script>
+<script src="/assets/js/parent.js"></script>
+
+<?php include __DIR__ . '/../includes/footer.php'; ?>