Add NHN Cloud credentials management and bump version to v0.0.19

- Add NHN Cloud credential fields to User model (tenant_id, username, encrypted password, storage_account)
- Add API endpoints for credentials CRUD operations
- Implement Fernet encryption for password storage

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

users/urls.py

@@ -2,7 +2,8 @@ from django.urls import path
 from .views import (
     RegisterView, MeView, CustomTokenObtainPairView,
     SSHKeyUploadView, SSHKeyInfoView, SSHKeyRetrieveView,
-    UserListView, UserUpdateView
+    UserListView, UserUpdateView,
+    NHNCloudCredentialsView, NHNCloudPasswordView
 )
 from rest_framework_simplejwt.views import TokenObtainPairView, TokenRefreshView, TokenVerifyView
 from .views_jwks import jwks_view # django-jwks
@@ -21,4 +22,7 @@ urlpatterns = [
     # 관리자용 사용자 관리 API
     path('users/', UserListView.as_view(), name='user_list'),
     path('users/<int:pk>/', UserUpdateView.as_view(), name='user_update'),
+    # NHN Cloud 자격증명 API
+    path('nhn-cloud/', NHNCloudCredentialsView.as_view(), name='nhn_cloud_credentials'),
+    path('nhn-cloud/password/', NHNCloudPasswordView.as_view(), name='nhn_cloud_password'),
 ]