While the embedded editor's preview sandbox boots, the pane shows a plain
text label for each step (Booting, Creating project, Installing packages,
Initializing dev server). Add an Angie pose above the label so the wait
tells a small story. Behaviour is unchanged; this is presentation only.

Poses map to the existing LoadingStep values:
  Starting / Booting / Creating project -> greeting
  Installing packages                   -> coding-01
  Initializing dev server               -> superhero

The mascot sits in a fixed-size box (object-fit: contain) so swapping
poses of different aspect ratios never shifts the label or progress bar.