Rework RedisTransport into plain get, mget, set, delete and eval methods,
split the breaker step (run_under_breaker over the existing
_run_under_circuit_breaker) from the events step (RedisServiceEvents.observe,
which skips the stack walk and event when no service_callback is set), and
add eval with EVALSHA plus EVAL fallback. Fold in the store layer and the
response polling store, and replace the redis-access skill references with
the migration plan and PR sketches.
