Allow the user to manage their own feed subscriptions

• Plus and edit buttons on hover of category? (not mobile friendly)
• Edit feeds button (in header?)
  • List with URLs and minimum sync interval

See https://watermelondb.dev/docs/Sync/Backend

Acceptance criteria:

• 10 items are rendered in the feed list
• If a category is selected, that category is rendered
• Infinite scroll
• Show description inline

The initial sync performance isn't great. This is due to two slowdowns

• When a user adds a feed subscription, they have to wait until the next sync interval for their changes to propagate to the server
• When the change does propagate to the server, we have to wait for the next cron interval to pick up and sync it

To address this we need to make two changes

1. Use reactive sync

Take advantage of the reactive dexie sync continuation to react to changes immediately. See https://dexie.org/docs/Syncable/Dexie.Syncable.ISyncProtocol#onsuccess--function-continuation

We need to make sure we can combine react and again - if not, we'll have to set up our own setInterval for pulling the next batch of changes

2. Sync new feeds immediately

When new subscriptions are created, we can run sync specifically for those feeds. To start with we can do this from within the sync lambda. Alternatively we can set up a queue with a new lambda. Its not super important to avoid duplication with the cron lambda, as the sync writes are idempotent.

Make sure to sync once the minimum requested sync interval has been reached in terms of age.

• Show count next to category
• Add "mark all as read"
• Add "mark as read" shortcut icon (optional)

• On the main page, show all recent stories instead of welcome message
• Add story list (story + decription + time published)
• When a story with content in story list is clicked, open in third panel
  • note: Use same view as used now (typography) but also add date and time
• When a story without content is clicked, open in new window (go to website)
• On mobile, make all 3 panels (feed list, story list, story reader) separate screens with ability to go back.
  Consider https://www.smashingmagazine.com/2022/04/breadcrumbs-ux-design/
  Consider https://ux.stackexchange.com/questions/25428/is-there-a-better-solution-than-breadcrumbs-to-cascading-categories-on-mobile

On mobile

• Long press -> menu with Unsubscribe only for now
  On non-mobile
• dot-dot-dot button shown on hover on the side

TODO: figure out how to force serviceworker to cache images after frontend feed sync, and figure out whether that makes sense.