engine-v0.5.1

Added

• IsolatedWordLineSplitterConfig.fallbackMinSecondsOnScreen, a looser time on screen tried only when no word reaches minSecondsOnScreen. Absent, the splitter behaves as before.
• LINE_NO_WRAP_CSS, the rule that keeps a line on one row, exported so a consumer can emit it in its own framework layer and let a stylesheet override white-space on .line.