feat: add Anthropic reasoning effort pricing controls

backend/internal/handler/gateway_handler.go

@@ -171,6 +171,19 @@ func (h *GatewayHandler) Messages(c *gin.Context) {
 	reqStream := parsedReq.Stream
 	bindRequestedReasoningEffort(c, body, reqModel)
 	ensureCompositeTargetPlatform(c, apiKey, reqModel)
+	if policyBody, changed, err := applyAnthropicReasoningEffortPolicyForRequest(c, apiKey, body); err != nil {
+		respondOpenAIReasoningEffortPolicyError(c, err, h.errorResponse)
+		return
+	} else if changed {
+		if err := parsedReq.ReplaceBody(policyBody); err != nil {
+			reqLog.Warn("gateway.reasoning_effort_policy_parse_failed", zap.Error(err))
+			h.errorResponse(c, http.StatusBadRequest, "invalid_request_error", "Failed to apply reasoning effort policy")
+			return
+		}
+		body = parsedReq.Body.Bytes()
+		reqModel = parsedReq.Model
+		reqStream = parsedReq.Stream
+	}
 	reqLog = reqLog.With(zap.String("model", reqModel), zap.Bool("stream", reqStream))
 
 	// 解析渠道级模型映射