feat(server): 初始化HTTP服务器并添加产品数据结构

- 创建基础HTTP服务器，监听localhost:5000
- 实现StringHandle结构体处理HTTP请求
- 添加请求日志打印功能
- 忽略/favicon.ico请求并返回404状态
- 定义Product结构体及示例数据
- 实现产品税费计算和折扣应用方法

24-httpserver/httpserver/product.go

@@ -0,0 +1,31 @@
+package main
+
+type Product struct {
+	Name, Category string
+	Price          float64
+}
+
+var Kayak = Product{
+	Name:     "Kayak",
+	Category: "Watersports",
+	Price:    279,
+}
+
+var ProductList = []Product{
+	{"Kayak", "Watersports", 279},
+	{"LifeJacket", "Watersports", 49.95},
+	{"Soccer Ball", "Soccer", 19.50},
+	{"Corner Flags", "Soccer", 34.95},
+	{"Stadium", "Soccer", 79500},
+	{"Thinking Cap", "Chess", 16},
+	{"Unsteady Chair", "Chess", 75},
+	{"Bling-Bling King", "Chess", 1200},
+}
+
+func (p *Product) AddTax() float64 {
+	return p.Price * 1.2
+}
+
+func (p *Product) ApplyDiscount(amount float64) float64 {
+	return p.Price - amount
+}