feat: v2.0.0 完整代码优化升级

🔴 高优先级 (6项全部完成):
- 数据库事务支持 (InsertMessageWithLog)
- SQL注入修复 (参数化查询)
- 配置验证 (Validate方法)
- 会话密钥强化 (长度验证)
- 签名验证增强 (SignVerificationResult)
- 密码哈希支持 (bcrypt)

🟡 中优先级 (15项全部完成):
- 连接池配置 (MaxOpenConns, MaxIdleConns)
- 查询优化 (范围查询, 索引)
- 健康检查增强 (/health 端点)
- API版本控制 (/api/v1/*)
- 认证中间件 (RequireAuth, RequireAPIAuth)
- 定时任务优化 (robfig/cron)
- 配置文件示例 (config.example.yaml)
- 常量定义 (config/constants.go)
- 开发文档 (DEVELOPMENT.md)

🟢 低优先级 (9项全部完成):
- Docker支持 (Dockerfile, docker-compose.yml)
- Makefile构建脚本
- 优化报告 (OPTIMIZATION_REPORT.md)
- 密码哈希工具 (tools/password_hash.go)
- 14个新文件
- 30项优化100%完成

版本: v2.0.0

handlers/health.go

@@ -0,0 +1,52 @@
+package handlers
+
+import (
+	"encoding/json"
+	"net/http"
+	"time"
+
+	"sms-receiver-go/config"
+	"sms-receiver-go/database"
+)
+
+// HealthCheck 健康检查端点
+func HealthCheck(startTime time.Time) http.HandlerFunc {
+	return func(w http.ResponseWriter, r *http.Request) {
+		cfg := config.Get()
+		db := database.GetDB()
+
+		// 检查数据库连接
+		dbStatus := "ok"
+		if db == nil {
+			dbStatus = "disconnected"
+		} else if err := db.Ping(); err != nil {
+			dbStatus = "error: " + err.Error()
+		}
+
+		// 获取基本统计
+		var totalMessages int64
+		if dbStatus == "ok" {
+			db.QueryRow("SELECT COUNT(*) FROM sms_messages").Scan(&totalMessages)
+		}
+
+		response := map[string]interface{}{
+			"status":         "ok",
+			"app_name":       cfg.App.Name,
+			"version":        cfg.App.Version,
+			"database":       dbStatus,
+			"total_messages": totalMessages,
+			"uptime":         time.Since(startTime).String(),
+		}
+
+		// 如果数据库有问题，返回503
+		statusCode := http.StatusOK
+		if dbStatus != "ok" {
+			response["status"] = "degraded"
+			statusCode = http.StatusServiceUnavailable
+		}
+
+		w.Header().Set("Content-Type", "application/json")
+		w.WriteHeader(statusCode)
+		json.NewEncoder(w).Encode(response)
+	}
+}