test(messages): add messages-openai suite covering Anthropic↔OpenAI translation (#5587)

## Summary

- Adds a new `messages-openai` integration test suite that reuses
`tests/integration/messages` with the `gpt` setup, so requests flow
through `_anthropic_to_openai` / `_openai_to_anthropic` in
`providers/inline/messages/impl.py` instead of the native passthrough
branch that the existing `messages` (ollama-reasoning) suite hits.
- Registers the suite in `tests/integration/ci_matrix.json` so
replay-mode CI runs it, and adds a `gpt` / `messages-openai` row to
`.github/workflows/record-integration-tests.yml` so future rerecord runs
refresh it.
- Includes 12 recordings captured against `openai/gpt-4o` so replay mode
works out-of-the-box (no API key required in CI).

This is a precursor to #5577 — the batches tests there need a suite that
targets OpenAI, because batches go through `create_message()` which only
exercises translation when the provider is not in
`_NATIVE_MESSAGES_MODULES`.

## Test plan

Recorded locally and verified against `openai/gpt-4o`:

```bash
./scripts/integration-tests.sh \
  --stack-config server:ci-tests \
  --suite messages-openai \
  --inference-mode record-if-missing
```

Result: 13/13 tests pass. Recording URLs point at
`https://api.openai.com/v1/chat/completions`, confirming the translation
path is being exercised (not the Anthropic-native `/v1/messages`
endpoint the ollama suite hits).

🤖 Generated with [Claude Code](https://claude.com/claude-code)

Signed-off-by: Charlie Doern <cdoern@redhat.com>

Author: cdoern

.github/workflows/record-integration-tests.yml

@@ -191,6 +191,8 @@ jobs:
             suite: base
           - setup: gpt
             suite: responses
+          - setup: gpt
+            suite: messages-openai
           - setup: azure
             suite: responses
           - setup: bedrock

tests/integration/ci_matrix.json

@@ -13,6 +13,7 @@
     {"suite": "vllm-reasoning", "setup": "vllm"},
     {"suite": "ollama-reasoning", "setup": "ollama-reasoning"},
     {"suite": "messages", "setup": "ollama-reasoning"},
+    {"suite": "messages-openai", "setup": "gpt"},
     {"suite": "interactions", "setup": "gemini"}
   ],
   "stainless": [