DNF90 服务端与启动器完整源码（含 GM 工具功能增强）

服务端（Go）：
- GM 塞背包/带属性装备发放：在线角色推送 op14 增量物品行，背包实时刷新，无需回角色选择界面
- GM 改金币/改等级：去掉在线拒绝，落库后推送 op14 钱包/op37 等级状态，在线实时刷新
- 等级端点统一切换到新版 GMSetCharacterLevel（自带在线刷新）
- 无限/锁死疲劳模式 + 燃烧疲劳：每房间消耗 2 点、打怪与通关经验双倍
- 燃烧疲劳开关时给所有在线角色推送系统提示（op12 mode 0）
- 深渊史诗掉率：GM 全局倍率 + 城镇增益药剂窗口倍率，真实接入掉落结算

启动器（Python/JS）：
- 标题栏自绘、窗口 1204x717、禁止拖拽改大小、仅最小化/关闭
- GM 工具：疲劳与燃烧、深渊史诗掉率、拍卖行上架（单一定价对齐）
- 拍卖行上架前端对齐服务端单一价格语义，修复 400 报错

server/internal/modules/dnf/repository/mail_system.go

@@ -0,0 +1,141 @@
+package repository
+
+import (
+	"context"
+	"errors"
+	"math"
+	"strconv"
+	"strings"
+	"time"
+)
+
+var ErrSystemMailInvalid = errors.New("system mailbox delivery is invalid")
+
+// SystemMailDelivery is a server-owned, non-expiring mail created by a
+// committed gameplay transaction. It deliberately has no player postage;
+// callers must supply transaction-scoped MailboxRepository instances so reward
+// consumption and the durable mail commit together.
+type SystemMailDelivery struct {
+	RecipientCharacterID string
+	RecipientName        string
+	Title                string
+	Body                 string
+	Source               string
+	CompletionKey        string
+	Gold                 int64
+	Attachments          []MailAttachment
+	CreatedAt            time.Time
+	// SenderCharacterID / SenderName 是**可选**的来源署名。
+	//
+	// 留空 = 系统邮件（寄件人显示"系统"），既有调用方一行都不用改。
+	// 商城赠送要填：收件人得看得出来这封礼物是谁送的。
+	// SenderName 只用于展示，绝不参与任何权限判定。
+	SenderCharacterID string
+	SenderName        string
+}
+
+// systemMailSenderName 是系统邮件的默认署名（寄件人显示"系统"）。
+// 与 AppendSystemMail 改动前的字面量完全一致：既有系统邮件（礼包溢出、GM 发信）
+// 的寄件人显示不能因为这次改动发生变化。
+const systemMailSenderName = "系统"
+
+// AppendSystemMail appends one non-expiring system mail to a character's
+// mailbox. It is safe to call only through the transaction supplied by the
+// relevant asset owner; this helper owns no transaction itself.
+func AppendSystemMail(ctx context.Context, repo MailboxRepository, delivery SystemMailDelivery) (string, error) {
+	recipientID := strings.TrimSpace(delivery.RecipientCharacterID)
+	if repo == nil || recipientID == "" || strings.TrimSpace(delivery.Source) == "" || delivery.Gold < 0 ||
+		(delivery.Gold == 0 && len(delivery.Attachments) == 0 && strings.TrimSpace(delivery.Title) == "" && strings.TrimSpace(delivery.Body) == "") {
+		return "", ErrSystemMailInvalid
+	}
+	attachments := cloneMailAttachments(delivery.Attachments)
+	for _, attachment := range attachments {
+		if attachment.ItemID <= 0 || attachment.Count <= 0 {
+			return "", ErrSystemMailInvalid
+		}
+	}
+
+	record, found, err := repo.Load(ctx, recipientID)
+	if err != nil {
+		return "", err
+	}
+	if !found {
+		record = MailboxRecord{CharacterID: recipientID}
+	}
+	if record.Mails == nil {
+		record.Mails = make(map[string]MailRecord)
+	}
+	completionKey := strings.TrimSpace(delivery.CompletionKey)
+	if completionKey != "" {
+		for mailID, existing := range record.Mails {
+			if strings.TrimSpace(existing.Metadata["completion_key"]) != completionKey {
+				continue
+			}
+			if existing.RecipientCharacterID != recipientID || existing.Gold != delivery.Gold ||
+				strings.TrimSpace(existing.Metadata["source"]) != strings.TrimSpace(delivery.Source) {
+				return "", ErrSystemMailInvalid
+			}
+			return mailID, nil
+		}
+	}
+	mailID, err := nextSystemMailID(record.Mails)
+	if err != nil {
+		return "", err
+	}
+	now := delivery.CreatedAt.UTC()
+	if now.IsZero() {
+		now = time.Now().UTC()
+	}
+	// 署名：留空 → 系统（与改动前逐字节一致）；商城赠送填赠送方，收件人看得出是谁送的。
+	senderCharacterID := strings.TrimSpace(delivery.SenderCharacterID)
+	if senderCharacterID == "" {
+		senderCharacterID = "0"
+	}
+	senderName := strings.TrimSpace(delivery.SenderName)
+	if senderName == "" {
+		senderName = systemMailSenderName
+	}
+	record.Mails[mailID] = MailRecord{
+		MailID:               mailID,
+		SenderCharacterID:    senderCharacterID,
+		SenderName:           senderName,
+		RecipientCharacterID: recipientID,
+		RecipientName:        strings.TrimSpace(delivery.RecipientName),
+		Title:                strings.TrimSpace(delivery.Title),
+		Body:                 strings.TrimSpace(delivery.Body),
+		Gold:                 delivery.Gold,
+		Attachments:          attachments,
+		CreatedAt:            now,
+		// A system overflow delivery must remain claimable until the player
+		// makes room. A zero expiry is the repository's durable non-expiring
+		// representation and is projected as such by the mailbox owner.
+		Metadata: map[string]string{
+			"source":         strings.TrimSpace(delivery.Source),
+			"system_mail":    "true",
+			"unlimited":      "true",
+			"completion_key": completionKey,
+		},
+	}
+	record.UpdatedAt = now
+	if err := SaveMailboxFields(ctx, repo, record, MailboxFieldMails); err != nil {
+		return "", err
+	}
+	return mailID, nil
+}
+
+func nextSystemMailID(mails map[string]MailRecord) (string, error) {
+	var max uint64
+	for key := range mails {
+		value, err := strconv.ParseUint(strings.TrimSpace(key), 10, 32)
+		if err != nil {
+			continue
+		}
+		if value > max {
+			max = value
+		}
+	}
+	if max >= math.MaxUint32 {
+		return "", ErrSystemMailInvalid
+	}
+	return strconv.FormatUint(max+1, 10), nil
+}