So unless you want to have problems you should definitely provide a way to access the SWD pins. They will not only allow debugging, SWD will allow programming in any situation, while UART or other options depend on you getting into the boot loader…
You should also expose nRST for a seamless experience.
To use SWD you need a STLink programmer, the STLink Mini v3 is cheap and ideally suited, but if it’s not available, an STLink v2 (there are also clones) is enough…
To use it you need the following connections:
gnd
swclk
swdio
nRST
vdd (output to STLink, not input)
Maybe adding a JST-SH connector is a solution?