Fix DHCP client unable to get IP and config not persisting

- Fixed verifyAssignment being too strict for new clients
- Fixed parseRequestedIP string conversion bug
- Fixed response sent to 0.0.0.0 instead of broadcast address
- Added SO_BROADCAST support for UDP socket
- Fixed session persistence after page refresh (localStorage)
- Added in-memory session store for auth middleware
- Added config reloader so DHCP server picks up web UI changes dynamically

install.sh

@@ -0,0 +1,169 @@
+#!/bin/bash
+
+# ========================================
+# DHCP & DNS 管理器 - Linux 安装脚本（修复版）
+# ========================================
+
+set -e
+
+INSTALL_DIR="/opt/dhcp-dns-manager"
+SERVICE_NAME="dhcp-dns-manager"
+
+echo "========================================"
+echo "  DHCP & DNS 管理器 - Linux 安装脚本"
+echo "========================================"
+echo ""
+
+# 检查是否以 root 运行
+if [ "$EUID" -ne 0 ]; then 
+    echo "❌ 请使用 sudo 运行此脚本"
+    echo "   sudo ./install.sh"
+    exit 1
+fi
+
+# 检测系统
+if [ -f /etc/debian_version ]; then
+    OS="debian"
+    echo "✓ 检测到 Debian/Ubuntu 系统"
+elif [ -f /etc/redhat-release ]; then
+    OS="redhat"
+    echo "✓ 检测到 RHEL/CentOS 系统"
+else
+    OS="unknown"
+    echo "⚠ 未识别的 Linux 发行版，尝试通用安装"
+fi
+
+# 安装依赖
+echo ""
+echo "📦 安装依赖..."
+
+if [ "$OS" = "debian" ]; then
+    apt update
+    apt install -y curl wget git build-essential
+elif [ "$OS" = "redhat" ]; then
+    yum install -y curl wget git gcc make
+fi
+
+# 检查 Go 环境
+if ! command -v go &> /dev/null; then
+    echo ""
+    echo "📦 安装 Go 环境..."
+    GO_VERSION="1.21.0"
+    wget -q https://go.dev/dl/go${GO_VERSION}.linux-amd64.tar.gz
+    tar -C /usr/local -xzf go${GO_VERSION}.linux-amd64.tar.gz
+    rm go${GO_VERSION}.linux-amd64.tar.gz
+    echo 'export PATH=$PATH:/usr/local/go/bin' >> /etc/profile
+    export PATH=$PATH:/usr/local/go/bin
+    echo "✓ Go 已安装"
+else
+    echo "✓ Go 环境已存在: $(go version)"
+fi
+
+# 创建安装目录
+echo ""
+echo "📁 创建安装目录..."
+mkdir -p $INSTALL_DIR
+
+# 复制文件
+echo ""
+echo "📋 复制项目文件..."
+cp -r ./* $INSTALL_DIR/
+
+# 编译程序
+echo ""
+echo "🔨 编译程序..."
+cd $INSTALL_DIR
+
+# 整理并下载依赖
+echo "整理依赖..."
+go mod tidy
+
+# 下载依赖
+echo "下载 Go 依赖..."
+go mod download
+
+# 编译
+echo "编译程序..."
+CGO_ENABLED=1 go build -o dhcp-dns-manager ./cmd
+
+# 创建数据目录
+mkdir -p $INSTALL_DIR/data
+chown -R root:root $INSTALL_DIR
+
+# 创建 systemd 服务
+echo ""
+echo "⚙️  创建 systemd 服务..."
+cat > /etc/systemd/system/$SERVICE_NAME.service << EOF
+[Unit]
+Description=DHCP & DNS Manager Service
+After=network.target
+Documentation=https://github.com/your-repo/dhcp-dns-manager
+
+[Service]
+Type=simple
+User=root
+WorkingDirectory=$INSTALL_DIR
+ExecStart=$INSTALL_DIR/dhcp-dns-manager -config $INSTALL_DIR/configs/config.json
+Restart=always
+RestartSec=5
+StandardOutput=journal
+StandardError=journal
+SyslogIdentifier=dhcp-dns-manager
+
+# 安全设置
+NoNewPrivileges=false
+ProtectSystem=false
+ProtectHome=false
+
+[Install]
+WantedBy=multi-user.target
+EOF
+
+# 重载 systemd
+systemctl daemon-reload
+
+# 配置防火墙
+echo ""
+echo "🔥 配置防火墙..."
+
+if command -v ufw &> /dev/null; then
+    echo "配置 UFW 防火墙..."
+    ufw allow 53/udp comment "DNS"
+    ufw allow 67/udp comment "DHCP"
+    ufw allow 8080/tcp comment "Web UI"
+elif command -v firewall-cmd &> /dev/null; then
+    echo "配置 Firewalld..."
+    firewall-cmd --permanent --add-port=53/udp
+    firewall-cmd --permanent --add-port=67/udp
+    firewall-cmd --permanent --add-port=8080/tcp
+    firewall-cmd --reload
+else
+    echo "⚠  未检测到防火墙工具，请手动配置"
+fi
+
+# 启动服务
+echo ""
+echo "🚀 启动服务..."
+systemctl enable $SERVICE_NAME
+systemctl start $SERVICE_NAME
+
+# 检查状态
+sleep 2
+echo ""
+echo "========================================"
+echo "  ✅ 安装完成！"
+echo "========================================"
+echo ""
+echo "服务状态：$(systemctl is-active $SERVICE_NAME)"
+echo ""
+echo "📱 Web 界面：http://$(hostname -I | awk '{print $1}'):8080"
+echo "👤 默认账号：admin / admin"
+echo ""
+echo "常用命令："
+echo "  查看状态：systemctl status $SERVICE_NAME"
+echo "  查看日志：journalctl -u $SERVICE_NAME -f"
+echo "  重启服务：systemctl restart $SERVICE_NAME"
+echo "  停止服务：systemctl stop $SERVICE_NAME"
+echo ""
+echo "⚠️  首次使用请修改默认密码！"
+echo ""