…ry tiers and re-inject, conformance v1.6.0

Implements R1 Redis for the Python runtime: Laravel-layout delayed
publish with a pcall-guarded reserve script, unconditional dead-lettering
of poison bodies (binding 1.1), ADR-0034 retry backoff for SQS, Kafka
retry tiers with a re-inject consumer, and the vendored conformance
suite bumped to v1.6.0 with no known gaps.

…s with Go

Kafka poison follows Go routePoison: dead-lettered to <topic>.dlq when the DLQ
is on, otherwise dropped on DELETE or sent down the bounded FAIL path. Retries
without tiers redeliver in place, and undecodable legacy Redis bodies settle
like the Go and Node transports.

…out lupa (#10)

* test: align Redis poison tests with ADR-0035 and skip lupa-only checks without lupa

* ci: run the Python 3.9 job on ubuntu-24.04

…ance job (#11)