Split isConnectedOnAllWay into a thin method that snapshots state and
a pure evalConnStatus helper that takes a connStatusInputs struct, so
the tri-state decision logic can be exercised without constructing
full Worker or Handshaker objects. Add table-driven tests covering
force-relay, ICE-unavailable and fully-available code paths, plus
unit tests for iceRetryState budget/hourly transitions and reset.