Zola's default feed templates include any non-draft page regardless of
its date field, so scheduled posts (date in the future, draft=false)
were showing up in the feed before they were meant to be public.
Override templates/atom.xml and templates/rss.xml with versions that
skip entries whose date is greater than now(). The filter is bypassed
on localhost so zola serve still previews scheduled posts locally,
matching the pattern already used in templates/section.html.
