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

fix-deps.sh

@@ -0,0 +1,47 @@
+#!/bin/bash
+
+# ========================================
+# 快速修复：解决依赖下载问题
+# ========================================
+
+set -e
+
+echo "🔧 DHCP & DNS 管理器 - 依赖修复脚本"
+echo "======================================"
+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
+
+echo "✓ Go 环境: $(go version)"
+echo ""
+
+# 进入项目目录
+cd "$(dirname "$0")"
+
+# 清理旧依赖
+echo "🗑️  清理旧依赖..."
+rm -f go.sum
+go clean -modcache
+
+# 下载并整理依赖
+echo "📦 下载并整理依赖..."
+go mod tidy
+
+# 编译
+echo "🔨 编译程序..."
+CGO_ENABLED=1 go build -o dhcp-dns-manager ./cmd
+
+echo ""
+echo "✅ 修复完成！"
+echo ""
+echo "现在可以运行:"
+echo "  ./dhcp-dns-manager -config configs/config.json"
+echo ""
+echo "或安装为系统服务:"
+echo "  sudo ./install.sh"
+echo ""