v0.9.2 CI Reliability Patch

Patch release for the v0.9 stability line after confirming main CI is green.\n\n- Fixes the CI install path by stubbing the optional openai-codex SDK in Codex Mode C tests when the codex extra is not installed.\n- Isolates the Channel E priming test from unrelated memory retrieval/RAG channels so unit tests do not hit slow embed work under CI timeout.\n- Keeps openai-codex and its CLI package out of animaworks[all-tools]; install animaworks[codex] explicitly when Mode C is needed.\n\nCI: https://github.com/xuiltul/animaworks/actions/runs/27806066508\n\nRecommended install target: animaworks==0.9.2.