provider request shape around the reset

payload-t2-01.json       messages= 10  bytes=  18358  roles=['developer', 'user', 'user', 'assistant', 'tool', 'assistant', 'tool', 'assistant', 'user', 'user']
payload-t2-02.json       messages=  2  bytes=  12204  roles=['developer', 'user']
payload-t3-01.json       messages=  5  bytes=  16519  roles=['developer', 'user', 'assistant', 'user', 'user']

payload-t2-01 = last request before the reset (full window)
payload-t2-02 = first request after the reset (window header only)
payload-t3-01 = new pi process, -c resume: same frozen header
