Fix update flow: resolve global registry correctly, update embedded template

- OnFileDownloaded now resolves oldComp via op.FAMREGISTRY instead of
  self.target_comp, preventing the embedded template inside TDFam_create
  from being destroyed during updates
- Clear old registry's opshortcut before rename to avoid dual-shortcut
  conflicts during the replacement window
- After successful update, copy the new registry back into TDFam_create
  so the project saves with the correct version and won't re-prompt
- Refresh family owners' fam_registry reference after embedded replacement
- Add .valid guard on deferred destroy of old registry
- Remove all debug prints from OpFamRegistryExt and ExtUpdater