chore(release): v0.2.7 — honest pins, visible managed model, physical delete

- A pinned playground model that is unavailable now errors clearly instead of
  silently answering from the managed local model (route_source no longer lies).
- The managed CMF model is surfaced in GET /admin/api/models (marked "managed",
  shown read-only in the UI) so the real running model is visible and pinnable
  without a hand-maintained [[models]] entry; a fresh install still lists nothing.
- Deleting a model now removes its local .cmf physically (file or tensor-dir);
  deleting the managed model also stops the server and clears the [cmf] config.
  Routing is stripped of the deleted id so the config still validates.

web/js/i18n/en.js

@@ -129,6 +129,8 @@ export default {
   "models.form.secretMissing": "not set",
   "models.form.secretPlaceholder": "set or replace key (write-only)",
   "models.deleteConfirm": "Delete model \"{id}\"?",
+  "models.managed": "managed",
+  "models.managedHint": "Provided by the managed CMF server (Settings → Local models). Configure it there.",
 
   // routing
   "routing.title": "Routing",