CwdSwitchAbortMode = Literal['resume', 'thread_switch']Which flow opened an abort-capable prompt, selecting the abort wording.
Passed as the prompt's abort argument; None there means abort is not
offered. "resume" is the launch-time -r resume (abort starts a new
session); "thread_switch" is the in-session /threads switcher (abort keeps
the current thread). Its members are kept disjoint from CwdSwitchChoice's as a
naming convention -- not a type guarantee (these are distinct Literal types
used at distinct sites, so a checker already keeps them apart) -- so a mode token
is never mistaken for an outcome token in a log, test, or debugger.
test_abort_mode_tokens_disjoint_from_choice enforces it.