Keep the reader view article date on one line (#9388)
Follow-up to #9369, as discussed in https://github.com/FreshRSS/FreshRSS/pull/9369#issuecomment-5954861516
Changes proposed in this pull request:
- In the reader view, the date in the line under the article title had a fixed `width: 155px`. A long date such as "28 September 2026 at 18:30" needs about 190px, so at desktop width it broke into two lines. This was already the case before #9369.
- `.content .subtitle.horizontal-list .item.date` now uses the 155px as `min-width` and has `white-space: nowrap`, so the box grows to fit the date and the date stays on one line.
- Short dates are unchanged: they keep the 155px box and the same position.
- If the feed name, authors and date do not fit on one row, the date moves to the next line as a whole (the `flex-wrap` from #9369), instead of breaking in the middle.
- In the `max-width: 840px` block the date is reset to `min-width: 0; white-space: normal`, so nothing can overflow on very narrow screens. The phone layout from #9369 is unchanged.
- `frss.rtl.css` was regenerated with `rtlcss`.
Abdelrhman Mohamed