P2R-09/10/11/12/13/14, P2-16/17/18 all marked done. Acceptance line
for Windows hosts annotated as 'compile-verified, untested in CI'.
_diag/p2-completion-sweep/ holds the dashboard + host-detail +
schedules + sources + repo + source-group-edit screenshots from a
clean sweep against :8080. Zero console errors throughout.
announce_test.go: rate-limit + global-cap subtests dropped t.Parallel
to avoid racing on the package-level tunables under -race.