* ci(studio): gate Studio open and timeline scroll on work counts that only go down
Beside the timeline viewport gate's ms budgets, count the work two Studio journeys do and hold
each count under a checked-in ceiling in perf-ceilings.json: thumbnail renders, page loads and
requests for opening a 12-scene film, and React commits, style recalcs and layouts per scroll
tick. Counts repeat exactly run to run, so a rise names the work that grew.
* ci(studio): hold style recalcs per scroll tick at the CI runner's count
* ci(studio): gate the median scroll run and list which thumbnails rendered
* ci(studio): set work-count ceilings from the CI runner's counts on main
* ci(studio): fail the open count loudly when Studio never starts
* ci(studio): fail a work-count gate that measured nothing
* ci(studio): a scroll counter missing from any measured run reads as not measured
* ci(studio): split the perf ratchet's CLI and page counters into small steps, and let its unit test count
* ci(studio): count scroll work in an untimed pass and commit the open fixture's scenes
* ci(studio): gate only the open journey's counts; scroll counts follow runner speed
* ci(studio): fail a dropped journey and an unreadable base in the work-count ratchet
* ci(studio): split the ratchet's checks into small functions
