feat(rcs): migrate all RCS APIs from rainyun-go-sdk

- 35 endpoints across 14 files, response structs split for reuse
- Reuse RcsRecord/Node/Plan/OsInfo/UsageData across list/detail/create
- Fix source bugs: {id} path placeholders, missing / in firewall pos path,
  missing body in ChargeRcsTrafic, resp vs &resp
- Add HTTPMethod_PATCH, common.BasicOperationResponse, VncConnectionInfo

apis/rcs/create_rcs.go

@@ -0,0 +1,36 @@
+package rcs
+
+import (
+	"github.com/XingfenD/rainyun_api_go_sdk/constant"
+)
+
+type CreateRcsRequest struct {
+	AddDiskSize  int    `json:"add_disk_size"`  // 额外硬盘容量GB
+	PlanID       int    `json:"plan_id"`        // 套餐ID
+	Duration     int    `json:"duration"`       // 创建时长(月)
+	OsID         int    `json:"os_id"`          // 系统ID
+	WithEipNum   int    `json:"with_eip_num"`   // 创建IP数量
+	WithEipFlags string `json:"with_eip_flags"` // 是否开启高防，us_ddosip -> 美国高防，nb_ddosip -> 宁波高防
+	WithEipType  string `json:"with_eip_type"`  // ipv4(默认)/ipv6
+	WithCouponID int    `json:"with_coupon_id"` // 优惠券ID
+	Try          bool   `json:"try"`            // 是否为试用
+	NodeUUID     string `json:"node_uuid"`      // 指定节点(管理员可用，用户不可用)
+	AppVars      []struct {
+		AppID int `json:"app_id"`
+		Vars  any `json:"vars,omitempty"`
+	} `json:"app_vars"` // 预装应用
+	Zone string `json:"zone"` // 内网可用区
+}
+
+type CreateRcsResponse struct {
+	Code int       `json:"code"`
+	Data RcsRecord `json:"data"`
+}
+
+func (s *RcsService) CreateRcs(req *CreateRcsRequest) (*CreateRcsResponse, error) {
+	path := "/product/rcs"
+
+	var resp CreateRcsResponse
+	err := s.client.Do(constant.HTTPMethod_POST, path, nil, req, &resp)
+	return &resp, err
+}