Add websockets to the dev extra so the repro harness smoke test can import
its websocket client dependency in the CI test matrix. Also apply ruff
formatting to the files the formatter check was rejecting so the 3.12 lint
job passes.
Unit 1 of the codex-proxy-resilience plan. Preload now iterates BOTH
the Anthropic and OpenAI transform pipelines, dedupes shared transforms
by id(), and merges the status dict into a typed WarmupRegistry so
/debug/warmup (Unit 5) and /readyz have one source of truth.
MemoryHandler._ensure_initialized gains an asyncio.Lock with a
double-checked pattern so concurrent first callers share one backend
init instead of racing. The body is wrapped in asyncio.wait_for with
STARTUP_INIT_TIMEOUT_SECONDS (default 30s) — on timeout _initialized
stays False so subsequent requests retry (fail-open contract).
Startup now also forces one embedder warm-up encode so the ONNX graph
is compiled synchronously at startup instead of lazily on the first
request. Best-effort: failures are logged, never raised.
