feat: 实现前端卡密管理界面

- 卡密列表展示与分页功能

- 单个/批量创建卡密

- 卡密删除与批量删除

- 卡密导出功能 (file-saver)

- 启用/禁用状态切换

- 状态判断 (有效/已使用/已失效)

- Toast 通知系统 (vue-sonner)

- 登录页面错误提示优化

- 后端登录错误消息中文化

backend/internal/models/admin.go

@@ -0,0 +1,23 @@
+package models
+
+import (
+	"database/sql"
+	"time"
+)
+
+// Admin 管理员表
+type Admin struct {
+	ID           int          `json:"id"`
+	Username     string       `json:"username"`
+	Email        string       `json:"email"`
+	PasswordHash string       `json:"-"` // 密码哈希不输出到 JSON
+	IsSuperAdmin bool         `json:"is_super_admin"`
+	IsActive     bool         `json:"is_active"`
+	CreatedAt    time.Time    `json:"created_at"`
+	LastLogin    sql.NullTime `json:"last_login"`
+}
+
+// TableName 返回表名
+func (Admin) TableName() string {
+	return "admins"
+}

backend/internal/models/api_key.go

@@ -0,0 +1,25 @@
+package models
+
+import (
+	"database/sql"
+	"time"
+)
+
+// APIKey API 密钥表
+type APIKey struct {
+	ID           int          `json:"id"`
+	Key          string       `json:"key"` // 格式: sk_live_xxx
+	Name         string       `json:"name"`
+	CreatedByID  int          `json:"created_by_id"`
+	IsActive     bool         `json:"is_active"`
+	RateLimit    int          `json:"rate_limit"`  // 次/分钟
+	AllowedIPs   string       `json:"allowed_ips"` // JSON 数组
+	LastUsed     sql.NullTime `json:"last_used"`
+	RequestCount int          `json:"request_count"`
+	CreatedAt    time.Time    `json:"created_at"`
+}
+
+// TableName 返回表名
+func (APIKey) TableName() string {
+	return "api_keys"
+}

backend/internal/models/card_key.go

@@ -0,0 +1,42 @@
+package models
+
+import (
+	"time"
+)
+
+// CardKey 卡密表
+type CardKey struct {
+	ID           int       `json:"id"`
+	Key          string    `json:"key"` // 格式: XXXX-XXXX-XXXX-XXXX
+	MaxUses      int       `json:"max_uses"`
+	UsedCount    int       `json:"used_count"`
+	ValidityType string    `json:"validity_type"` // month/quarter/year/custom
+	ExpiresAt    time.Time `json:"expires_at"`
+	IsActive     bool      `json:"is_active"`
+	CreatedByID  int       `json:"created_by_id"`
+	CreatedAt    time.Time `json:"created_at"`
+}
+
+// TableName 返回表名
+func (CardKey) TableName() string {
+	return "card_keys"
+}
+
+// IsExpired 检查卡密是否过期
+func (c *CardKey) IsExpired() bool {
+	return time.Now().After(c.ExpiresAt)
+}
+
+// IsUsable 检查卡密是否可用
+func (c *CardKey) IsUsable() bool {
+	return c.IsActive && !c.IsExpired() && c.UsedCount < c.MaxUses
+}
+
+// RemainingUses 返回剩余使用次数
+func (c *CardKey) RemainingUses() int {
+	remaining := c.MaxUses - c.UsedCount
+	if remaining < 0 {
+		return 0
+	}
+	return remaining
+}

backend/internal/models/chatgpt_account.go

@@ -0,0 +1,109 @@
+package models
+
+import (
+	"database/sql"
+	"encoding/json"
+	"time"
+)
+
+// ChatGPTAccount ChatGPT Team 账号表
+type ChatGPTAccount struct {
+	ID                  int          `json:"id"`
+	Name                string       `json:"name"`
+	AuthToken           string       `json:"-"` // Token 不输出到 JSON
+	TeamAccountID       string       `json:"team_account_id"`
+	SeatsInUse          int          `json:"seats_in_use"`
+	SeatsEntitled       int          `json:"seats_entitled"`
+	ActiveStart         sql.NullTime `json:"-"`
+	ActiveUntil         sql.NullTime `json:"-"`
+	IsActive            bool         `json:"is_active"`
+	ConsecutiveFailures int          `json:"consecutive_failures"`
+	LastCheck           sql.NullTime `json:"-"`
+	LastUsed            sql.NullTime `json:"-"`
+	CreatedAt           time.Time    `json:"created_at"`
+	UpdatedAt           sql.NullTime `json:"-"`
+}
+
+// ChatGPTAccountJSON 用于 JSON 序列化的结构
+type ChatGPTAccountJSON struct {
+	ID                  int     `json:"id"`
+	Name                string  `json:"name"`
+	TeamAccountID       string  `json:"team_account_id"`
+	SeatsInUse          int     `json:"seats_in_use"`
+	SeatsEntitled       int     `json:"seats_entitled"`
+	ActiveStart         *string `json:"active_start"`
+	ActiveUntil         *string `json:"active_until"`
+	IsActive            bool    `json:"is_active"`
+	ConsecutiveFailures int     `json:"consecutive_failures"`
+	LastCheck           *string `json:"last_check"`
+	LastUsed            *string `json:"last_used"`
+	CreatedAt           string  `json:"created_at"`
+	UpdatedAt           *string `json:"updated_at"`
+	AvailableSeats      int     `json:"available_seats"`
+	UsagePercentage     float64 `json:"usage_percentage"`
+}
+
+// MarshalJSON 自定义 JSON 序列化
+func (a ChatGPTAccount) MarshalJSON() ([]byte, error) {
+	j := ChatGPTAccountJSON{
+		ID:                  a.ID,
+		Name:                a.Name,
+		TeamAccountID:       a.TeamAccountID,
+		SeatsInUse:          a.SeatsInUse,
+		SeatsEntitled:       a.SeatsEntitled,
+		IsActive:            a.IsActive,
+		ConsecutiveFailures: a.ConsecutiveFailures,
+		CreatedAt:           a.CreatedAt.Format(time.RFC3339),
+		AvailableSeats:      a.AvailableSeats(),
+		UsagePercentage:     a.UsagePercentage(),
+	}
+
+	if a.ActiveStart.Valid {
+		s := a.ActiveStart.Time.Format(time.RFC3339)
+		j.ActiveStart = &s
+	}
+	if a.ActiveUntil.Valid {
+		s := a.ActiveUntil.Time.Format(time.RFC3339)
+		j.ActiveUntil = &s
+	}
+	if a.LastCheck.Valid {
+		s := a.LastCheck.Time.Format(time.RFC3339)
+		j.LastCheck = &s
+	}
+	if a.LastUsed.Valid {
+		s := a.LastUsed.Time.Format(time.RFC3339)
+		j.LastUsed = &s
+	}
+	if a.UpdatedAt.Valid {
+		s := a.UpdatedAt.Time.Format(time.RFC3339)
+		j.UpdatedAt = &s
+	}
+
+	return json.Marshal(j)
+}
+
+// TableName 返回表名
+func (ChatGPTAccount) TableName() string {
+	return "chatgpt_accounts"
+}
+
+// AvailableSeats 返回可用席位数量
+func (a *ChatGPTAccount) AvailableSeats() int {
+	return a.SeatsEntitled - a.SeatsInUse
+}
+
+// UsagePercentage 返回席位使用百分比
+func (a *ChatGPTAccount) UsagePercentage() float64 {
+	if a.SeatsEntitled == 0 {
+		return 0
+	}
+	return float64(a.SeatsInUse) / float64(a.SeatsEntitled) * 100
+}
+
+// IsSubscriptionValid 检查订阅是否有效
+func (a *ChatGPTAccount) IsSubscriptionValid() bool {
+	if !a.ActiveUntil.Valid {
+		return false
+	}
+	return time.Now().Before(a.ActiveUntil.Time)
+}

backend/internal/models/invitation.go

@@ -0,0 +1,43 @@
+package models
+
+import (
+	"database/sql"
+	"time"
+)
+
+// InvitationStatus 邀请状态枚举
+type InvitationStatus string
+
+const (
+	StatusPending  InvitationStatus = "pending"
+	StatusSent     InvitationStatus = "sent"
+	StatusAccepted InvitationStatus = "accepted"
+	StatusFailed   InvitationStatus = "failed"
+	StatusExpired  InvitationStatus = "expired"
+)
+
+// Invitation 邀请记录表
+type Invitation struct {
+	ID           int              `json:"id"`
+	CardKeyID    sql.NullInt64    `json:"card_key_id"`
+	AccountID    int              `json:"account_id"`
+	InvitedEmail string           `json:"invited_email"`
+	Status       InvitationStatus `json:"status"`
+	ErrorMessage sql.NullString   `json:"error_message"`
+	ExpiresAt    sql.NullTime     `json:"expires_at"`
+	CreatedAt    time.Time        `json:"created_at"`
+	UpdatedAt    sql.NullTime     `json:"updated_at"`
+}
+
+// TableName 返回表名
+func (Invitation) TableName() string {
+	return "invitations"
+}
+
+// IsExpired 检查邀请是否过期
+func (i *Invitation) IsExpired() bool {
+	if !i.ExpiresAt.Valid {
+		return false
+	}
+	return time.Now().After(i.ExpiresAt.Time)
+}