I'm a secondary school teacher.
Don't go in being confrontational or all guns blazing.
PE teachers are always having to deal with kids who are trying to get off sports. Their reality is that they are endlessly getting emails and notes and so on from parents saying X has a cold, X has their period, X has stubbed their toe, can they not do PE today, and it's a pain in the arse for them. A lot of kids are trying it on and it causes them a lot of admin and logistical difficulties sorting out the kids who are skiving from the ones who are genuinely unwell or injured. I wouldn't do their job!
Also, bear in mind that communication systems in many schools are shit. The PE teacher may not know your daughter has ongoing respiratory issues - you'll be surprised how much important stuff doesn't get recorded or circulated. In my school only people with certain admin rights can add notes about students' health or whatever to our internal systems, and if an email gets overlooked or someone doesn't have time to put the note on the system, then pretty vital information can end up not being circulated to staff. You also have to bear in mind that PE teachers don't get much time at their desks, so they can miss emails and so on due to being outside for much of the teaching day.
I wouldn't be having a meeting at this stage as there's nothing that's happened here other than eye rolls and muttering - which your daughter has assumed are about her but might not have been, so that's not fact - and the threat of a behaviour point, which may be down to the teacher not being made fully aware of the health issues.
I would send an email to the Head of PE and the PE teacher, with the HOY copied in, reminding them of your daughter's medical needs and the fact that she is currently off PE due to her chest, as per doctor's advice. I would then ask what the plan is for her during PE, given that you don't want her participating in practical lessons until she is cleared to do so by the doctor. I would also raise the behaviour point and say that your daughter is very upset to have been assumed to be bunking off, and that you would appreciate the PE teacher apologising and making it clear that there had been a misunderstanding next time she sees her.
Only if that email is not acted on would I escalate to requesting a meeting with the Head of PE and Head of Year.