- Yahoo news and the Reddit and StockTwits feeds serve only recent items, so a
historical window trimmed to nothing was reported as "no news" or "no
posts", and the sentiment analyst scored that silence as a neutral signal
- judge each empty window in one shared rule: it is a real absence only when
the feed's coverage reaches the window's first day and the window ends by
today; otherwise report it unavailable with where coverage starts
- coverage comes from the returned timestamps, which are newest-first on these
feeds, plus Reddit's one-week search lookback; merged global-news searches
prove no continuity and are bounded by the present alone
- state in the sentiment analyst that historical sentiment inputs are not
guaranteed to be point-in-time