config: set default judge_model=gpt-5, embedding_model=text-embedding-3-small

gpt-5.4/5.5/5.2/5.4-mini/5.4-nano are incompatible with RAGAS 0.4.3
because they require max_completion_tokens instead of max_tokens.
gpt-5 / gpt-4.1 support max_tokens and json_object mode required by RAGAS.

Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>

webapp/api/score.py

@@ -91,7 +91,7 @@ def score_sample(
     - `semantic_similarity` — 回答与参考答案的语义相似度（需 ground_truth）
 
     **推荐模型配置**：
-    - `judge_model`: `gpt-5.4`
+    - `judge_model`: `gpt-5`
     - `embedding_model`: `text-embedding-3-small`
 
     **鉴权**：若 `.env` 中配置了 `SCORE_API_TOKEN`，需在请求头携带