pg-prev/pg-next deliberately skip comCarregando (it would fight the
page-boundary disabled-state logic), so nothing stopped two rapid clicks
from firing overlapping GET /api/leads requests. If the earlier page's
response resolved after the later one, it silently overwrote the table,
pager text and prev/next disabled state with a page the operator was no
longer viewing. Adds a per-call sequence number in carregarTabela(); a
response is only applied if no newer call has started since, covering
every caller (pager clicks, filter changes, tab activation) with one guard.
Found via a full-project audit; verified the regression test fails
against the pre-fix code and passes against the fix.