feat(user): implement OTP login, user creation, and profile management

- Added SendOTP method for simulating OTP sending.
- Implemented LoginWithOTP method for user login/registration via OTP, including user creation if not found.
- Added Me method to retrieve current user information.
- Implemented Update method for updating user profile details.
- Added RealName method for real-name verification.
- Implemented GetNotifications method to fetch user notifications.
- Created user_test.go for comprehensive unit tests covering login, profile retrieval, updates, real-name verification, and notifications.
- Updated database models to use appropriate consts for fields like gender, status, and roles.

backend/database/models/users.query.gen.go

@@ -36,7 +36,7 @@ func newUser(db *gorm.DB, opts ...gen.DOOption) userQuery {
 	_userQuery.VerifiedAt = field.NewTime(tableName, "verified_at")
 	_userQuery.Nickname = field.NewString(tableName, "nickname")
 	_userQuery.Avatar = field.NewString(tableName, "avatar")
-	_userQuery.Gender = field.NewString(tableName, "gender")
+	_userQuery.Gender = field.NewField(tableName, "gender")
 	_userQuery.Bio = field.NewString(tableName, "bio")
 	_userQuery.Birthday = field.NewField(tableName, "birthday")
 	_userQuery.Location = field.NewJSONB(tableName, "location")
@@ -67,7 +67,7 @@ type userQuery struct {
 	VerifiedAt         field.Time
 	Nickname           field.String
 	Avatar             field.String
-	Gender             field.String
+	Gender             field.Field
 	Bio                field.String
 	Birthday           field.Field
 	Location           field.JSONB
@@ -104,7 +104,7 @@ func (u *userQuery) updateTableName(table string) *userQuery {
 	u.VerifiedAt = field.NewTime(table, "verified_at")
 	u.Nickname = field.NewString(table, "nickname")
 	u.Avatar = field.NewString(table, "avatar")
-	u.Gender = field.NewString(table, "gender")
+	u.Gender = field.NewField(table, "gender")
 	u.Bio = field.NewString(table, "bio")
 	u.Birthday = field.NewField(table, "birthday")
 	u.Location = field.NewJSONB(table, "location")