feat(p1y-alpha): add OpenAI-compatible LeaBench adapter (benchmark only)

Adapter de benchmark isole (hors runtime Lea) ciblant un serveur
/v1/chat/completions a support vision (vLLM/SGLang/TGI), pour comparer
plus tard a Ollama via LeaBench. Ne controle jamais le desktop.

- core/evaluation/openai_compat_lea_bench_adapter.py : payload data-URL
  image_url, parsing choices[0].message.content. Reutilise par import la
  logique prompt/parse/normalisation de ollama_lea_bench_adapter (zero refactor).
- tools/lea_bench_openai_compat.py : wrapper CLI (--base-url defaut :8001).
- tests/unit/test_openai_compat_lea_bench_adapter.py : 6 tests mockes HTTP
  (data URL, pas de fuite expectation/click_region, prediction valide,
  abstain safe sur HTTP!=200 et reponse malformee, JSONL rechargeable).

Aucun runtime Lea modifie. Aucun service lance.

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

tools/lea_bench_openai_compat.py

@@ -0,0 +1,15 @@
+#!/usr/bin/env python3
+"""CLI wrapper for the OpenAI-compatible LeaBench adapter (benchmark only)."""
+
+import sys
+from pathlib import Path
+
+ROOT = Path(__file__).resolve().parents[1]
+if str(ROOT) not in sys.path:
+    sys.path.insert(0, str(ROOT))
+
+from core.evaluation.openai_compat_lea_bench_adapter import main
+
+
+if __name__ == "__main__":
+    raise SystemExit(main())