Add k3s cluster expansion documentation and scripts

- Complete expansion guide for 2/4/6 node scenarios
- Quick join scripts for worker and master nodes
- Health check and diagnostic scripts
- Quick reference card for common operations

php-test/submit.php

@@ -0,0 +1,50 @@
+<?php
+require_once 'Database.php';
+
+header('Content-Type: application/json; charset=utf-8');
+
+if ($_SERVER['REQUEST_METHOD'] !== 'POST') {
+    header('Location: index.php');
+    exit;
+}
+
+try {
+    // 获取表单数据
+    $name = trim($_POST['name'] ?? '');
+    $email = trim($_POST['email'] ?? '');
+    $message = trim($_POST['message'] ?? '');
+
+    // 验证必填字段
+    if (empty($name) || empty($email)) {
+        throw new Exception('姓名和邮箱为必填项');
+    }
+
+    // 验证邮箱格式
+    if (!filter_var($email, FILTER_VALIDATE_EMAIL)) {
+        throw new Exception('邮箱格式不正确');
+    }
+
+    // 获取数据库连接
+    $db = Database::getConnection();
+
+    // 准备SQL语句
+    $sql = "INSERT INTO test_data (name, email, message) VALUES (:name, :email, :message)";
+    $stmt = $db->prepare($sql);
+
+    // 绑定参数并执行
+    $stmt->execute([
+        ':name' => $name,
+        ':email' => $email,
+        ':message' => $message
+    ]);
+
+    // 重定向到首页并显示成功消息
+    header('Location: index.php?status=success');
+    exit;
+
+} catch (Exception $e) {
+    // 重定向到首页并显示错误消息
+    $errorMsg = urlencode($e->getMessage());
+    header('Location: index.php?status=error&msg=' . $errorMsg);
+    exit;
+}