🚀 Feature: Auto-generate meta previews & loading state with dist/index.html

[JoshuaKGoldberg]

Bug Report Checklist

• I have tried restarting my IDE and the issue persists.
• I have pulled the latest main branch of the repository.
• I have searched for related issues and found none that matched my issue.

Expected

I'd like to have JoshuaKGoldberg/ChooseYourFramework#13 be done automatically: so the game's preview image is used as a loading image.

In addition, the default generated dist/index.html file for dist games right now, as managed by shenanigans-manager, doesn't come with many SEO / social media <meta> tags. How about creating a meta value for "shenanigans" settings in the package.json that includes an array of FrameTickr tick waits and/or InputWritr commands to generate a social media preview image?

[
  { "ticks": 10, "type": "tick" },
  { "group": "onkeydown", "key": "left", "type": "input" },
  { "ticks": 10, "type": "tick" },
  { "group": "onkeydown", "key": "down", "type": "input" }
]

I'm wondering if I should switch these packages to a shenanigans.json... #300

Additional Info

No response