ui: P2R-09 auto-init UX — init line in chrome + danger-zone re-init

Latest 'init' job status surfaced under the host-detail vitals strip
(succeeded/failed/running/queued, with link to the live job log on
non-success). New POST /hosts/{id}/repo/reinit handler dispatches a
fresh init job after the operator types the host name to confirm;
audit row records 'host.repo_reinit'.

internal/server/http/server.go

@@ -228,6 +228,7 @@ func (s *Server) routes(r chi.Router) {
 		r.Post("/hosts/{id}/repo/credentials", s.handleUIRepoCredentialsSave)
 		r.Post("/hosts/{id}/repo/bandwidth", s.handleUIRepoBandwidthSave)
 		r.Post("/hosts/{id}/repo/maintenance", s.handleUIRepoMaintenanceSave)
+		r.Post("/hosts/{id}/repo/reinit", s.handleUIRepoReinit)
 		// Admin credentials form (separate slot for prune-capable user).
 		r.Post("/hosts/{id}/admin-credentials", s.handleUIAdminCredentialsSave)
 		r.Post("/hosts/{id}/admin-credentials/delete", s.handleUIAdminCredentialsDelete)