We should store HTML and Markdown in IndexedDB instead of localStorage

[vanpelt]

In my local development environment I was getting quota exceeded errors because of the amount of data we're writing to local storage. frontend/src/state/atoms/history.ts contains logic to read and write the HTML and the Markdown for a HistoryItem to localStorage. We should rewrite that to use indexedDB (using jotai-minidb) in a way that maintains backwards compatibility and reads from localStorage falling back to indexedDB and moving all future writes to indexedDB.