For WISCA: simulations are distributed across (group, chunk) job pairs
via future.apply::future_lapply(), keeping all workers active even when
the regimen count is smaller than nbrOfWorkers(). Sequential fallback
with progress ticker is preserved when parallel = FALSE or workers = 1.
For grouped antibiograms: each group is processed by a separate worker,
mirroring the row-batch approach in as.sir().
Same gate pattern as as.sir() (PR #280): requires a non-sequential
future::plan() to be active; auto-upgrades to parallel = TRUE when a
parallel plan is detected; throws an informative error otherwise.
https://claude.ai/code/session_01FC43syPbzhGmKgrrVNHjnF
