Add snippets in the mobile app

[bobness]

• Show it on the share modal (components/ShareModal.tsx)
• Add checkbox to make it a "draft" so snippets can be added later
• Allow followers (eventually, subscribers) to propose snippets (like a pull request)

[bobness]

Closing as a dupe of https://github.com/bobness/inspect-app/issues/34 (woops)