In the quiet arithmetic of global finance, a single disappointing American jobs report on Friday was enough to shift the balance between two of the world's most watched currencies. The yen rose nearly half a percent against the dollar, settling at ¥157.76, as traders recalibrated their expectations for Federal Reserve rate cuts — and with them, the relative appeal of holding dollars. Yet the movement carried a second layer of meaning: both Japanese and American authorities have recently intervened in currency markets, and every organic shift in the yen's favor now raises the question of whethe