fix: include region in default error message for @IsPhoneNumber

Author: dami0806

packages/express-cargo/src/validator.ts

@@ -475,7 +475,7 @@ export function IsPhoneNumber(region?: CountryCode, message?: cargoErrorMessage)
                 propertyKey,
                 'isPhoneNumber',
                 (value: unknown) => typeof value === 'string' && isValidPhoneNumber(value, region),
-                message || `${String(propertyKey)} must be a valid phone number`,
+                message || `${String(propertyKey)} must be a valid phone number${region ? ` for ${region}` : ''}`,
             ),
         )
     }

packages/express-cargo/tests/validator/isPhoneNumber.test.ts

@@ -42,6 +42,10 @@ describe('isPhoneNumber decorator', () => {
             .getValidators()
             ?.find(v => v.type === 'isPhoneNumber')
 
+        it('should have region in default message', () => {
+            expect(krRule?.message).toBe('phone must be a valid phone number for KR')
+        })
+
         it('should pass for valid Korean numbers', () => {
             expect(krRule!.validate('+821012345678')).toBeNull()
             expect(krRule!.validate('01012345678')).toBeNull()