Remove demo references and add theme gallery

contest-styles.json

@@ -288,20 +288,6 @@
         },
         "preview": "[date time user] @host - /path"
     },
-    {
-      "id": "demo",
-      "name": "Demo",
-      "tagline": "Auto-rotate all themes",
-      "description": "Cycles through all themes each prompt for rapid screenshots.",
-      "layout": {
-        "line1": "auto",
-        "line2": "auto"
-      },
-      "colors": {
-        "note": "Uses each theme's native palette"
-      },
-      "preview": "(auto-rotate)"
-    },
     {
       "id": "radar",
       "name": "Radar",