docs: enhance /api/score OpenAPI docs with full Chinese docstring and response example

- Add detailed Chinese route docstring covering all 7 metrics, contexts format,
  ground_truth optional behavior, and Bearer auth instructions
- Add 200 response content example for Swagger UI Try-it-out
- Bump app version to 0.3.0

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

webapp/server.py

@@ -92,7 +92,7 @@ def create_app() -> FastAPI:
             "- **报告 API** — 查询历史运行记录与评估报告\n\n"
             "> **快速开始**：调用 `POST /api/pipeline/jobs` 传入 PDF 文件夹路径即可启动完整评估流程。"
         ),
-        version="0.2.0",
+        version="0.3.0",
         openapi_tags=OPENAPI_TAGS,
     )