bookmark polling strategy for the server

[xuatz]

Depends on #39

In xbo, we store a cache of the bookmarks from the original providers for a few reasons:

• users of xbo may have a ridiculous amount of bookmarks, and providers' api may not be able to serve us fast enough cheap enough
• we also would like to do additional processing on top of these bookmarks in the background when the user is not active (e.g. generate report, curate a sublist, group bookmarks from different providers)
• a naive approach when trying to request for bookmarks from providers cause us to exceed the api call limit and get us rate limited or banned

So when a user has providers connected, xbo should on a schedule make a request to respectively each provider, to query to see if there are:

• new bookmarks
• updated/missing bookmarks
  • missing bookmarks because the users might edit/move/delete bookmarks on the provider's own website
    we need to consider how we will handle this, perhaps ignore, flag it or something smarter

And depending on the API, they way they handle cursor/pagination and updated since may be different, so we will need to implement a strategy for each of them.

And then ultimately, store these bookmarks in pocketbase and make it available for the UI to query and render.

At this point of time, I think that the bookmarks should not be transformed, but kept and stored as-is from the providers. Then we can have a 1-1 record that handles the metadata of said bookmark, for example if it is archived, soft-deleted, hard-deleted, category, etc.