feat: 移除PDI和订单号字段，新增设备巡检模块

- 从物料跟踪页面移除订单号列和表单字段
- 从导航菜单移除PDI管理，添加设备巡检
- 新增InspectionLocation和InspectionRecord后端模型和API
- 新增设备巡检前端页面（左侧点位列表，右侧设备和历史记录）

backend/app/models/pdi.py

@@ -0,0 +1,59 @@
+import enum
+from sqlalchemy import Column, Integer, String, Float, DateTime, Text, Enum, func
+from app.database import Base
+
+
+class L3Status(str, enum.Enum):
+    pending   = "pending"
+    sent      = "sent"
+    confirmed = "confirmed"
+    cancelled = "cancelled"
+
+
+class L2Status(str, enum.Enum):
+    pending    = "pending"
+    processing = "processing"
+    done       = "done"
+
+
+class PDIRecord(Base):
+    """PDI (Process Data Input) – per-coil process order from L3."""
+    __tablename__ = "pdi_records"
+
+    id               = Column(Integer, primary_key=True, index=True)
+    coil_no          = Column(String(30), nullable=False, index=True, comment="卷号")
+    order_no         = Column(String(30), nullable=True, comment="订单号")
+    customer         = Column(String(100), nullable=True, comment="客户名称")
+    steel_grade      = Column(String(30), nullable=True, comment="钢种")
+
+    # 几何规格
+    thickness        = Column(Float, nullable=True, comment="来料厚度 mm")
+    width            = Column(Float, nullable=True, comment="来料宽度 mm")
+    target_thickness = Column(Float, nullable=True, comment="目标厚度 mm")
+    target_width     = Column(Float, nullable=True, comment="目标宽度 mm")
+
+    # 力学性能
+    yield_strength   = Column(Float, nullable=True, comment="屈服强度 MPa")
+    tensile_strength = Column(Float, nullable=True, comment="抗拉强度 MPa")
+    elongation       = Column(Float, nullable=True, comment="延伸率 %")
+
+    # 卷重/尺寸
+    coil_weight      = Column(Float, nullable=True, comment="卷重 kg")
+    inner_diameter   = Column(Float, nullable=True, comment="内径 mm")
+    outer_diameter   = Column(Float, nullable=True, comment="外径 mm")
+
+    # 工艺
+    process_route    = Column(String(100), nullable=True, comment="工艺路径 e.g. P1+P2+P3+P4+P5+P6")
+    priority         = Column(Integer, default=3, comment="优先级 1-5")
+
+    # 状态
+    l3_status        = Column(Enum(L3Status), default=L3Status.pending, comment="L3状态")
+    l2_status        = Column(Enum(L2Status), default=L2Status.pending, comment="L2状态")
+
+    # 时间戳
+    send_time        = Column(DateTime, nullable=True, comment="下发时间")
+    confirm_time     = Column(DateTime, nullable=True, comment="确认时间")
+
+    remark           = Column(Text, nullable=True, comment="备注")
+    created_at       = Column(DateTime, server_default=func.now())
+    updated_at       = Column(DateTime, server_default=func.now(), onupdate=func.now())