feat(models): ask whether to delete the model file from disk

- The delete button now opens a dialog; for local models it includes an "also
  delete the model file from disk" checkbox (checked by default), so a pool
  entry can be removed while keeping the .cmf for later.
- DELETE /admin/api/models/:id accepts ?delete_file=true|false (default true).
  The shared-file guard still applies: a file referenced by another model is
  never removed.
- cmf_file_for_model now treats any loopback base_url as local (managed servers
  can sit on any port, not just the legacy local_port).

web/js/i18n/en.js

@@ -132,6 +132,8 @@ export default {
   "models.form.secretMissing": "not set",
   "models.form.secretPlaceholder": "set or replace key (write-only)",
   "models.deleteConfirm": "Delete model \"{id}\"?",
+  "models.deleteFile": "also delete the model file from disk",
+  "models.deletedWithFile": "Deleted (file removed from disk)",
   "models.form.idOrModel": "Enter an id or a model name",
   "models.form.apiKey": "API Key",
   "models.form.apiKeyPlaceholder": "paste your API key",

web/js/i18n/ru.js

@@ -131,6 +131,8 @@ export default {
   "models.form.secretMissing": "не задан",
   "models.form.secretPlaceholder": "задать или заменить ключ (только запись)",
   "models.deleteConfirm": "Удалить модель \"{id}\"?",
+  "models.deleteFile": "также удалить файл модели с диска",
+  "models.deletedWithFile": "Удалено (файл стёрт с диска)",
   "models.form.idOrModel": "Укажите id или имя модели",
   "models.form.apiKey": "API-ключ",
   "models.form.apiKeyPlaceholder": "вставьте API-ключ",