feat: 算力引擎 Go 后端核心（new-api）

- 统一 OpenAI 兼容 /v1 中继 + 渠道/额度/令牌/流水
- 各领域包：relay 模型网关、model 数据层、controller 管理 API

middleware/email-verification-rate-limit.go

@@ -0,0 +1,72 @@
+package middleware
+
+import (
+	"fmt"
+	"net/http"
+
+	"github.com/QuantumNous/new-api/common"
+
+	"github.com/gin-gonic/gin"
+)
+
+const (
+	EmailVerificationRateLimitMark = "EV"
+	EmailVerificationMaxRequests   = 2  // 30秒内最多2次
+	EmailVerificationDuration      = 30 // 30秒时间窗口
+)
+
+func redisEmailVerificationRateLimiter(c *gin.Context) {
+	allowed, _, ttlSeconds, err := redisFixedWindowTake(
+		c.Request.Context(),
+		redisIPRateLimitKey(EmailVerificationRateLimitMark, c.ClientIP()),
+		EmailVerificationMaxRequests,
+		EmailVerificationDuration,
+	)
+	if err != nil {
+		memoryEmailVerificationRateLimiter(c)
+		return
+	}
+	if allowed {
+		c.Next()
+		return
+	}
+
+	waitSeconds := int64(EmailVerificationDuration)
+	if ttlSeconds > 0 {
+		waitSeconds = ttlSeconds
+	}
+
+	c.JSON(http.StatusTooManyRequests, gin.H{
+		"success": false,
+		"message": fmt.Sprintf("发送过于频繁，请等待 %d 秒后再试", waitSeconds),
+	})
+	c.Abort()
+}
+
+func memoryEmailVerificationRateLimiter(c *gin.Context) {
+	key := EmailVerificationRateLimitMark + ":" + c.ClientIP()
+
+	if !inMemoryRateLimiter.Request(key, EmailVerificationMaxRequests, EmailVerificationDuration) {
+		c.JSON(http.StatusTooManyRequests, gin.H{
+			"success": false,
+			"message": "发送过于频繁，请稍后再试",
+		})
+		c.Abort()
+		return
+	}
+
+	c.Next()
+}
+
+func EmailVerificationRateLimit() gin.HandlerFunc {
+	// Keep the fallback ready before requests arrive so a concurrent Redis
+	// outage cannot race the in-memory limiter's first initialization.
+	inMemoryRateLimiter.Init(common.RateLimitKeyExpirationDuration)
+	return func(c *gin.Context) {
+		if common.RedisEnabled {
+			redisEmailVerificationRateLimiter(c)
+		} else {
+			memoryEmailVerificationRateLimiter(c)
+		}
+	}
+}