HX-Boost is not always sent in all AJAX requests that htmx sends, only
those initiated by an element with hx-boost enabled. It was not showing
up on requests following an HX-Redirect response.
After reading the docs more, I realized HX-Target was what I wanted. If
I can see that the request is targeting `#main-content` then I know to
only return HTML inside that element. Simple.
In the process, also improve the feedback from the import/add feed
forms.
I also replaced the frontend code to replace utc timestamps with local
time strings with @hotwired/stimulus with vanilla js.
Currently, this allows the browser to subscribe to the response of the
asynchronous crawl after they add a new feed.
Eventually I will also use this in the main scheduled crawls. Right now,
it only upserts feed metadata based on the parsed feed.
