refactor(models): Remove TableName methods and use global table prefix

- Add DB.Prefix "vb_" to cfg.DB config for global table prefix
    - Remove TableName() methods from all models (User, Role, Permission, etc.)
    - Remove Role.Scope field and its unique index with Code
    - Let GORM auto-generate table names with configured prefix

cfg/cfg.go

@@ -53,8 +53,9 @@ type InitAdminConfig struct {
 // Global全局配置实例
 var Global = &Options{
 	DB: config.Database{
-		Type: "mysql",
-		DSN:  "root:123456@tcp(127.0.0.1:3306)/vbase?charset=utf8&parseTime=True&loc=Local",
+		Type:   "mysql",
+		Prefix: "vb_",
+		DSN:    "root:123456@tcp(127.0.0.1:3306)/vbase?charset=utf8&parseTime=True&loc=Local",
 	},
 	Redis: config.Redis{
 		Addr: "memory",
@@ -63,7 +64,7 @@ var Global = &Options{
 	StoragePath: "./data",
 	JWT: JWTConfig{
 		Secret:        "",
-		AccessExpiry:  time.Hour,
+		AccessExpiry:  time.Hour * 24,
 		RefreshExpiry: 30 * 24 * time.Hour,
 		Issuer:        "vbase",
 	},

models/auth.go

@@ -36,25 +36,16 @@ type Permission struct {
 	Role *Role `json:"role,omitempty" gorm:"foreignKey:RoleID;references:ID"`
 }
 
-func (Permission) TableName() string {
-	return "permissions"
-}
-
 // Role 角色表
 type Role struct {
 	vigo.Model
-	Scope       string `json:"scope" gorm:"uniqueIndex:idx_role_scope_code;size:50;default:'default'" desc:"作用域"`
-	Code        string `json:"code" gorm:"uniqueIndex:idx_role_scope_code;size:50" desc:"角色代码"`
+	Code        string `json:"code" gorm:"uniqueIndex;size:50" desc:"角色代码"`
 	Name        string `json:"name" desc:"角色名称"`
 	Description string `json:"description" desc:"角色描述"`
 	IsSystem    bool   `json:"is_system" desc:"是否系统预设角色"`
 	Status      int    `json:"status" gorm:"default:1" desc:"状态: 1=启用, 0=禁用"`
 }
 
-func (Role) TableName() string {
-	return "roles"
-}
-
 // UserRole 用户角色关联表
 type UserRole struct {
 	vigo.Model
@@ -67,10 +58,6 @@ type UserRole struct {
 	Role Role `json:"role,omitempty" gorm:"foreignKey:RoleID;references:ID"`
 }
 
-func (UserRole) TableName() string {
-	return "user_roles"
-}
-
 // GrantRoleRequest 授予角色请求
 type GrantRoleRequest struct {
 	Scope    string     `json:"scope" desc:"作用域"`

models/email.go

@@ -22,7 +22,3 @@ type EmailLog struct {
 	MessageID string  `gorm:"size:100" json:"message_id"`
 }
 
-// TableName 表名
-func (EmailLog) TableName() string {
-	return "email_logs"
-}

models/oauth.go

@@ -28,10 +28,6 @@ type OAuthClient struct {
 	Owner User `json:"owner,omitempty" gorm:"foreignKey:OwnerID;references:ID"`
 }
 
-func (OAuthClient) TableName() string {
-	return "oauth_clients"
-}
-
 // OAuthAuthorizationCode OAuth2.0 授权码
 type OAuthAuthorizationCode struct {
 	vigo.Model
@@ -50,10 +46,6 @@ type OAuthAuthorizationCode struct {
 	User   User        `json:"user,omitempty" gorm:"foreignKey:UserID;references:ID"`
 }
 
-func (OAuthAuthorizationCode) TableName() string {
-	return "oauth_authorization_codes"
-}
-
 // OAuthToken OAuth2.0 令牌
 type OAuthToken struct {
 	vigo.Model
@@ -71,10 +63,6 @@ type OAuthToken struct {
 	User   User        `json:"user,omitempty" gorm:"foreignKey:UserID;references:ID"`
 }
 
-func (OAuthToken) TableName() string {
-	return "oauth_tokens"
-}
-
 // OAuthClientStatus 客户端状态
 const (
 	OAuthClientStatusDisabled = 0

models/oauth_provider.go

@@ -41,11 +41,6 @@ type OAuthProvider struct {
 	IsBuiltIn bool `json:"is_built_in" gorm:"default:false"`
 }
 
-// TableName 表名
-func (OAuthProvider) TableName() string {
-	return "oauth_providers"
-}
-
 // OAuthProviderExtra 常用特殊配置键
 const (
 	OAuthExtraAppIDParam     = "appid_param"     // 微信: appid 参数名不同

models/setting.go

@@ -26,11 +26,6 @@ type Setting struct {
 	UpdatedBy string `gorm:"size:36" json:"updated_by"`
 }
 
-// TableName 表名
-func (Setting) TableName() string {
-	return "settings"
-}
-
 // 配置分类常量
 const (
 	SettingCategoryAuth     = "auth"

models/user.go

@@ -27,11 +27,6 @@ type User struct {
 	LastLoginAt   *time.Time `json:"last_login_at"`
 }
 
-// TableName 表名
-func (User) TableName() string {
-	return "users"
-}
-
 // Identity 第三方身份绑定
 type Identity struct {
 	vigo.Model
@@ -49,10 +44,6 @@ type Identity struct {
 	User User `json:"user,omitempty" gorm:"foreignKey:UserID;references:ID"`
 }
 
-func (Identity) TableName() string {
-	return "identities"
-}
-
 // Session 登录会话
 type Session struct {
 	vigo.Model
@@ -69,10 +60,6 @@ type Session struct {
 	User User `json:"user,omitempty" gorm:"foreignKey:UserID;references:ID"`
 }
 
-func (Session) TableName() string {
-	return "sessions"
-}
-
 // UserStatus 用户状态常量
 const (
 	UserStatusDisabled = 0

models/verification.go

@@ -27,11 +27,6 @@ type VerificationCode struct {
 	RemoteIP  string     `gorm:"size:50" json:"remote_ip"`
 }
 
-// TableName 表名
-func (VerificationCode) TableName() string {
-	return "verification_codes"
-}
-
 // CodeStatus 验证码状态
 type CodeStatus int