feat: support merchant team roles and permissions

backend/internal/model/merchant.go

@@ -25,6 +25,15 @@ const (
 	MemberRoleFinance  = "finance"
 	MemberRoleViewer   = "viewer"
 
+	PermissionMembersManage   = "members:manage"
+	PermissionProductsManage  = "products:manage"
+	PermissionOrdersManage    = "orders:manage"
+	PermissionWalletView      = "wallet:view"
+	PermissionWalletLedger    = "wallet:ledger"
+	PermissionRechargeManage  = "recharge:manage"
+	PermissionAPIManage       = "api:manage"
+	PermissionCallbacksManage = "callbacks:manage"
+
 	FeeTypeRate  = "rate"  // 手续费按百分比
 	FeeTypeFixed = "fixed" // 手续费按固定金额
 
@@ -104,6 +113,18 @@ type MerchantMember struct {
 	User     *User     `gorm:"foreignKey:UserID" json:"user,omitempty"`
 }
 
+// MerchantRole 是商户内可配置的员工角色；负责人仍是系统保留角色。
+type MerchantRole struct {
+	ID          uint      `gorm:"primarykey" json:"id"`
+	CreatedAt   time.Time `json:"created_at"`
+	UpdatedAt   time.Time `json:"updated_at"`
+	MerchantID  uint      `gorm:"not null;uniqueIndex:idx_merchant_role_code;index" json:"merchant_id"`
+	Code        string    `gorm:"size:64;not null;uniqueIndex:idx_merchant_role_code" json:"code"`
+	Name        string    `gorm:"size:64;not null" json:"name"`
+	Permissions string    `gorm:"type:text;not null;default:''" json:"permissions"`
+	Status      int       `gorm:"not null;default:1" json:"status"`
+}
+
 // APIClient 为一个商户的外部系统集成凭证。SecretCiphertext 仅保存加密后的密钥。
 type APIClient struct {
 	ID        uint           `gorm:"primarykey" json:"id"`