Install Codex plugin on OpenAI model selection (#78799)

* route openai agent runs through codex

* fix: load codex plugin for implicit openai runtime

* docs: credit openai codex auth fix

* fix(agents): respect custom openai runtime routing

* fix(agents): install codex plugin on openai selection

* fix(agents): preserve OpenAI Codex auth switching

* fix(ci): restore channel contract runner expression

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Co-authored-by: Vincent Koc <vincentkoc@ieee.org>

.github/workflows/ci.yml

@@ -854,7 +854,7 @@ jobs:
     name: ${{ matrix.checkName }}
     needs: [preflight]
     if: needs.preflight.outputs.run_checks_fast == 'true'
-    runs-on: ${{ github.repository == 'openclaw/openclaw' && needs.preflight.outputs.runner_4vcpu_ubuntu || 'ubuntu-24.04' }}
+    runs-on: ${{ github.repository == 'openclaw/openclaw' && 'blacksmith-4vcpu-ubuntu-2404' || 'ubuntu-24.04' }}
     timeout-minutes: 60
     strategy:
       fail-fast: false