Isolate realtime voice SDK upgrades at the worker boundary

When a Pipecat voice service depends on a newer frame contract than an existing cascaded worker, give it a separate pinned dependency set and deployment image. Keep the old pipeline and tests on their original pin, then prove the new worker with its own startup, media, and persistence checks. A package-wide upgrade can change structural behavior even when imports succeed; a passing local constructor test cannot prove live audio. This applies to staged voice migrations, not a recommendation to keep duplicate runtimes indefinitely.

Applies when: adding a newer Pipecat realtime service beside a working pinned voice pipeline. Keywords: Pipecat realtime live voice dependency pin worker Docker regression isolation