ROTATION becomes N flows — the header's bubble strip goes dynamic

The 'Flows' popdown moved from the header's right side to sit where the numbered bubble strip lives, and now actually switches which flow is active — 'Improve a CSV' (the original 6-step pipeline, with strategyCurator un-spliced back out of it), 'Build Corpora' (1 step), and a third, 'Augment a CSV of Event Attendees' (2 steps), added minutes later at zero architecture cost. FlowWidget's bubble count is no longer a fixed constant; it resizes to whatever the active flow's rotation actually is.