README: full-screen the Space (fullWidth + header: mini)

Tells the Hub to render the iframe at full width and swap the default
header chrome for a small floating one, so the multi-tab demo claims
the whole viewport.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

README.md

@@ -6,6 +6,11 @@ colorTo: indigo
 sdk: docker
 app_port: 7860
 pinned: false
+# Render full-screen on the Hub: full-width iframe + small floating
+# header instead of the default Hub chrome. Lets the multi-tab demo
+# claim the whole viewport.
+fullWidth: true
+header: mini
 ---
 
 # Carbon · DNA Continuation