ci(e2e-ui): remove OPENAI_API_KEY/BASE_URL from test runner env

The conftest's live_server fixture now injects mock LLM server
credentials (OPENAI_BASE_URL=mock_url/v1, OPENAI_API_KEY=mock-key)
into the spawned server subprocess directly — no real gateway
credentials needed for the openai-agents harness.

The OPENAI_API_KEY and OPENAI_BASE_URL env vars that flowed from the
CI job env into the runner are no longer needed and are removed.
LLM_API_KEY and the native-claude/codex gateway config are kept for
the native render-parity tests (claude-sdk/codex CLIs still need
real credentials via ~/.omnigent/config.yaml).

Co-authored-by: Isaac

.github/workflows/e2e-ui.yml

@@ -258,11 +258,12 @@ jobs:
         # --ui-skip-build: the SPA was built in the previous step.
         # --tracing/--screenshot/--video default to off; retain-on-failure
         # keeps green runs cheap while capturing artifacts on failures.
-        # OPENAI_API_KEY / OPENAI_BASE_URL flow into the spawned server via
-        # the conftest's live_server fixture for the openai-agents harness.
+        # OPENAI_API_KEY / OPENAI_BASE_URL are set by the conftest's
+        # live_server fixture to point at the in-process mock LLM server —
+        # no real gateway credentials needed for the openai-agents harness.
+        # Native render-parity tests (claude-sdk/codex) still use the
+        # ~/.omnigent/config.yaml written in the step above.
         env:
-          OPENAI_API_KEY: ${{ env.LLM_API_KEY }}
-          OPENAI_BASE_URL: ${{ secrets.GATEWAY_BASE_URL }}
           # Scheduled / manually dispatched runs are the full pass;
           # PR and push runs exclude @pytest.mark.nightly tests.
           NIGHTLY_FULL: ${{ github.event_name == 'schedule' || github.event_name == 'workflow_dispatch' }}