Bidirectional Class - First Strong Isolate

First Strong Isolate is a directional formatting character, specifically U+2068, that sets the base paragraph direction for any text that follows it, overriding the default auto-detection from the surrounding context. It acts as a neutral marker, meaning that the enclosed text is treated as an isolated sequence, and the directionality of the first strong directional character within that sequence determines the overall direction, either left to right or right to left. This prevents external neighbouring text from influencing the internal direction, and vice versa, ensuring that embedded segments like quotes, numbers, or user input retain their own logical ordering without causing mismatched bidi reordering across boundaries. The isolation terminates at the matching Pop Directional Format character.