feat(linkage): 计划-鞍座-实绩-停机联动 + 成本管理页

后端：
- 计划录入即「准备好」，队首(最早)自动「在线」(唯一)
- 新增上卷鞍座联动引擎 line_service：移动→鞍座→(有速度/投入生产)→生产中
  →带头达2000m→生产完成并自动产生实绩、持久化运行数据
- 停机自动检测：线速度为0持续>10min 自动新增待补充停机记录，恢复后自动结束
- /plan/start=移动到鞍座, 新增 /plan/{id}/commit 投入生产, /plan/saddle/current,
  /plan/seed 批量插入(轧制力模式)；后台引擎循环自动推进
- 新增成本管理：CostRecord 模型 + /cost CRUD + 9 类成本项(乳化液/盐酸/碱/电/水/蒸汽…)

前端：
- 入口跟踪重构为单个上卷鞍座工位(实时速度/带头长度进度/投入生产)+待上卷卡片+队列，
  计划列表/卡片/队列均可「移动」
- 新增成本管理页(成本项切换 + 柱+线图 + 明细表 + 时间筛选 + 新增)，布局参考乳化液耗量统计

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

backend/app/api/plan.py

@@ -9,6 +9,7 @@ from app.models.plan import ProductionPlan
 from app.schemas.plan import PlanCreate, PlanUpdate, PlanOut, PlanTemplate
 from app.schemas.common import Response, PageResponse
 from app.services.auth_service import get_current_user
+from app.services import line_service
 
 router = APIRouter()
 
@@ -42,6 +43,8 @@ async def list_plans(
     db: AsyncSession = Depends(get_db),
     _ = Depends(get_current_user),
 ):
+    # 拉取前保证队首自动上线（鞍座推进/停机检测由 /saddle 与后台引擎负责）
+    await line_service.ensure_online(db)
     query = select(ProductionPlan).order_by(desc(ProductionPlan.plan_date))
     if status:
         query = query.where(ProductionPlan.status == status)
@@ -80,6 +83,9 @@ async def create_plan(
     plan = ProductionPlan(**body.model_dump(), created_by=current_user.username)
     db.add(plan)
     await db.flush()
+    # 录入即准备好；若当前无在线计划，则队首自动上线
+    await line_service.ensure_online(db)
+    await db.refresh(plan)
     return Response.ok(PlanOut.model_validate(plan))
 
 
@@ -121,21 +127,85 @@ async def confirm_plan(plan_id: int, db: AsyncSession = Depends(get_db), _ = Dep
 
 
 @router.patch("/{plan_id}/start", response_model=Response[PlanOut])
-async def start_producing(plan_id: int, db: AsyncSession = Depends(get_db), _ = Depends(get_current_user)):
-    """移动到入口，开始生产：本条→producing，其它 producing→online（单卷在产）。"""
+async def move_to_saddle(plan_id: int, db: AsyncSession = Depends(get_db), _ = Depends(get_current_user)):
+    """移动：把在线计划推到上卷鞍座（等待速度/投入生产）。"""
     result = await db.execute(select(ProductionPlan).where(ProductionPlan.id == plan_id))
     plan = result.scalar_one_or_none()
     if not plan:
         raise HTTPException(status_code=404, detail="计划不存在")
-    # 其它正在生产的全部回退为在线（强制单卷在产）
-    others = await db.execute(
-        select(ProductionPlan).where(
-            ProductionPlan.status == "producing",
-            ProductionPlan.id != plan_id,
-        )
-    )
-    for o in others.scalars():
-        o.status = "online"
-    plan.status = "producing"
+    try:
+        await line_service.move_to_saddle(db, plan)
+    except ValueError as e:
+        raise HTTPException(status_code=400, detail=str(e))
     await db.flush()
+    await db.refresh(plan)
     return Response.ok(PlanOut.model_validate(plan))
+
+
+@router.patch("/{plan_id}/commit", response_model=Response[PlanOut])
+async def commit_producing(plan_id: int, db: AsyncSession = Depends(get_db), _ = Depends(get_current_user)):
+    """投入生产：把鞍座上的计划置为生产中（兜底未实时变化的数据）。"""
+    result = await db.execute(select(ProductionPlan).where(ProductionPlan.id == plan_id))
+    plan = result.scalar_one_or_none()
+    if not plan:
+        raise HTTPException(status_code=404, detail="计划不存在")
+    await line_service.commit_plan(db, plan)
+    await db.flush()
+    await db.refresh(plan)
+    return Response.ok(PlanOut.model_validate(plan))
+
+
+@router.get("/saddle/current", response_model=Response[Optional[PlanOut]])
+async def get_saddle(db: AsyncSession = Depends(get_db), _ = Depends(get_current_user)):
+    """上卷鞍座当前计划（含实时速度/已生产长度），并推进联动。"""
+    await line_service.tick(db)
+    res = await db.execute(select(ProductionPlan).where(ProductionPlan.on_saddle == 1))
+    plan = res.scalars().first()
+    return Response.ok(PlanOut.model_validate(plan) if plan else None)
+
+
+@router.post("/seed", response_model=Response[dict])
+async def seed_plans(count: int = 50, db: AsyncSession = Depends(get_db), current_user = Depends(get_current_user)):
+    """批量插入准备好的计划（轧制力模式），用于演示联动。"""
+    import random
+    from datetime import timedelta
+    res = await db.execute(select(func.count()).select_from(ProductionPlan))
+    base = (res.scalar() or 0)
+    grades = ["QStE340TM", "SPHC", "SAPH440", "B510L", "QTGLG-2019"]
+    now = datetime.now()
+    created = 0
+    for i in range(count):
+        seq = base + i + 1
+        it = round(random.uniform(2.0, 5.0), 2)
+        pt = round(it - random.uniform(0.0, 0.1), 2)
+        iw = random.choice([1000, 1050, 1100, 1150, 1200, 1250])
+        wt = round(random.uniform(15.0, 26.0), 3)
+        plan = ProductionPlan(
+            plan_no=f"PL{now:%Y%m%d}{seq:04d}",
+            plan_date=now + timedelta(minutes=i),
+            status="ready",
+            cold_coil_no=f"C{now:%y%m%d}{seq:04d}",
+            hot_coil_no=f"H{now:%y%m%d}{seq:04d}",
+            steel_grade=random.choice(grades),
+            incoming_thickness=it,
+            product_thickness=pt,
+            deviation_upper=0.05,
+            deviation_lower=-0.05,
+            incoming_width=iw,
+            product_width=iw - random.choice([0, 4, 6]),
+            packaging_req=random.choice(["裸包", "筒包"]),
+            trim_req=random.choice(["切边", "不切边"]),
+            rolling_mode="轧制力模式",
+            coil_diameter=random.choice([1450, 1500, 1550]),
+            split_count=1,
+            next_process="冷轧",
+            incoming_weight=wt,
+            incoming_od=random.choice([1400, 1450, 1500]),
+            split_weights=[wt],
+            created_by=current_user.username,
+        )
+        db.add(plan)
+        created += 1
+    await db.flush()
+    await line_service.ensure_online(db)
+    return Response.ok({"created": created})