feat(vlm): sort versions by newest first in VLM view, with disabled sort dropdown

When viewing all versions of a model (VLM mode via 'x versions' button):
- Backend always sorts by version ID descending, ignoring current sort_by
- A temporary 'Newest version first' option is injected into the sort
  dropdown (removed on exit, not a permanent option)
- The sort dropdown is disabled (greyed out) while VLM is active
- On clearing VLM, the previous sort preference is restored and the
  dropdown re-enabled
- Handles stale VLM state (e.g. after page reload with leftover session)
- Covers all three model page types: loras, checkpoints, embeddings

Also fixes review nits:
- Correct i18n call pattern (defaultValue in options object)
- Shared _restoreSortAfterVlm() helper to avoid triple duplication

static/js/components/controls/CheckpointsControls.js

@@ -102,6 +102,7 @@ export class CheckpointsControls extends PageControls {
             removeSessionItem('vlm_model_name');
             removeSessionItem('vlm_base_model');
             removeSessionItem('vlm_page_type');
+            this._restoreSortAfterVlm();
             // Hide the indicator
             const indicator = document.getElementById('customFilterIndicator');
             if (indicator) {