Make first-level as header

In my setup, I hide the customized top level heading

#import "@preview/hydra:0.6.2": hydra
#set page(header: context hydra(1, skip-starting: false))

#show heading.where(level: 1): it => align(center, block(it.body))
#set heading(numbering: (first, ..nums) => numbering("A.1.", ..nums))
#show heading.where(level: 1): it => [
  #pagebreak()
  #it
]

= Chapter 1

== Some title

I wonder if we can hide/suppress the dot in the header.