chore(ci): 后端 CI 增加 ruff format 检查并登记 blame 忽略清单

.github/workflows/build.yml

@@ -26,6 +26,8 @@ jobs:
         run: cd backend && uv sync --group dev
       - name: Lint
         run: cd backend && uv run ruff check src
+      - name: Format check
+        run: cd backend && uv run ruff format --check src
       - name: Dead code
         run: cd backend && uv run vulture
       - name: Type check