feat(gpu-service): scope create forms by the selected organization

In the platform-admin "all organizations" view, add an organization picker
(the CreateOrgScopeField slot) to the SSH public key, storage type,
storage, GPU instance and instance-template create forms, placed below the
name / display-name fields. Drop the hidden owner field and let the owner
derive from the request context, matching the model-route form.

For GPU instances, scope the instance-type list to clusters the chosen org
owns (client-side, by cluster owner) so an instance can't be scheduled onto
another org's cluster; when the org owns none, show "no instance type
available" and clear the selection, cluster and CPU/memory fields. Instance
templates gain a Global level (NULL owner) and an owner tag on the card.

src/locales/ja-JP/gpuservice.ts

@@ -96,6 +96,8 @@ export default {
   'gpuservice.instance.templates': 'インスタンステンプレート',
   'gpuservice.instance.section.storage': 'ストレージボリューム',
   'gpuservice.instance.type.required': 'インスタンスタイプを選択してください',
+  'gpuservice.instance.type.noAvailable':
+    '利用可能なインスタンスタイプがありません',
   'gpuservice.instance.gpuCount': 'GPU 数',
   'gpuservice.instance.gpuCount.required': 'GPU 数を入力してください',
   'gpuservice.instance.gpuCount.max':