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

start.sh

@@ -0,0 +1,56 @@
+#!/bin/bash
+
+echo "🚀 DHCP & DNS 管理器 - 快速启动脚本"
+echo "===================================="
+
+# 检查是否使用 Docker
+if command -v docker &> /dev/null && command -v docker-compose &> /dev/null; then
+    echo ""
+    echo "检测到 Docker 环境，使用 Docker 部署..."
+    echo ""
+    
+    # 创建数据目录
+    mkdir -p data configs
+    
+    # 如果配置文件不存在，复制默认配置
+    if [ ! -f configs/config.json ]; then
+        echo "创建默认配置文件..."
+        cp configs/config.json.example configs/config.json 2>/dev/null || true
+    fi
+    
+    # 启动服务
+    docker-compose up -d
+    
+    echo ""
+    echo "✅ 服务已启动！"
+    echo ""
+    echo "📱 Web 界面：http://localhost:8080"
+    echo "👤 默认账号：admin / admin"
+    echo ""
+    echo "查看日志：docker-compose logs -f"
+    echo "停止服务：docker-compose down"
+    
+else
+    echo ""
+    echo "未检测到 Docker，使用本地运行模式..."
+    echo ""
+    
+    # 检查 Go 环境
+    if ! command -v go &> /dev/null; then
+        echo "❌ 错误：未找到 Go 环境"
+        echo "请先安装 Go: https://golang.org/dl/"
+        exit 1
+    fi
+    
+    # 创建数据目录
+    mkdir -p data
+    
+    # 下载依赖
+    echo "下载依赖..."
+    go mod download
+    
+    # 运行
+    echo ""
+    echo "启动服务..."
+    go run ./cmd -config configs/config.json
+fi