main:新增并发控制功能

变更内容：
- 增加 `max_concurrent_jobs` 配置项，支持设置最大并发任务数。
- 为 `JobManager` 添加信号量控制实现任务并发限制。
- 新增获取任务并发状态的接口 `/jobs/concurrency/status`。
- 编写并发控制功能相关的测试用

src/functional_scaffold/api/models.py

@@ -152,3 +152,21 @@ class JobStatusResponse(BaseModel):
     result: Optional[Dict[str, Any]] = Field(None, description="执行结果（仅完成时返回）")
     error: Optional[str] = Field(None, description="错误信息（仅失败时返回）")
     metadata: Optional[Dict[str, Any]] = Field(None, description="元数据信息")
+
+
+class ConcurrencyStatusResponse(BaseModel):
+    """并发状态响应"""
+
+    model_config = ConfigDict(
+        json_schema_extra={
+            "example": {
+                "max_concurrent": 10,
+                "available_slots": 7,
+                "running_jobs": 3,
+            }
+        }
+    )
+
+    max_concurrent: int = Field(..., description="最大并发任务数")
+    available_slots: int = Field(..., description="当前可用槽位数")
+    running_jobs: int = Field(..., description="当前运行中的任务数")

src/functional_scaffold/api/routes.py

@@ -15,6 +15,7 @@ from .models import (
     JobCreateResponse,
     JobStatusResponse,
     JobStatus,
+    ConcurrencyStatusResponse,
 )
 from .dependencies import get_request_id
 from ..algorithms.prime_checker import PrimeChecker
@@ -292,3 +293,57 @@ async def get_job_status(job_id: str):
                 "message": str(e),
             },
         )
+
+
+@router.get(
+    "/jobs/concurrency/status",
+    response_model=ConcurrencyStatusResponse,
+    summary="查询并发状态",
+    description="查询任务管理器的并发执行状态",
+    responses={
+        200: {"description": "成功", "model": ConcurrencyStatusResponse},
+        503: {"description": "服务不可用", "model": ErrorResponse},
+    },
+)
+async def get_concurrency_status():
+    """
+    查询并发状态
+
+    返回当前任务管理器的并发执行状态，包括：
+    - 最大并发任务数
+    - 当前可用槽位数
+    - 当前运行中的任务数
+    """
+    try:
+        job_manager = await get_job_manager()
+
+        # 检查任务管理器是否可用
+        if not job_manager.is_available():
+            raise HTTPException(
+                status_code=status.HTTP_503_SERVICE_UNAVAILABLE,
+                detail={
+                    "error": "SERVICE_UNAVAILABLE",
+                    "message": "任务管理器不可用",
+                },
+            )
+
+        concurrency_status = job_manager.get_concurrency_status()
+
+        return ConcurrencyStatusResponse(
+            max_concurrent=concurrency_status["max_concurrent"],
+            available_slots=concurrency_status["available_slots"],
+            running_jobs=concurrency_status["running_jobs"],
+        )
+
+    except HTTPException:
+        raise
+
+    except Exception as e:
+        logger.error(f"查询并发状态失败: {str(e)}", exc_info=True)
+        raise HTTPException(
+            status_code=status.HTTP_500_INTERNAL_SERVER_ERROR,
+            detail={
+                "error": "INTERNAL_ERROR",
+                "message": str(e),
+            },
+        )