feat: 밸브 분류 시스템 및 구매 관리 시스템 기초 구현

✅ 밸브 분류 시스템:
- VALVE 상세 정보 저장 로직 추가 (backend/app/routers/files.py)
- 프론트엔드 밸브 사양서 표시 로직 추가 (MaterialsPage.jsx)
- 밸브 분류기 테스트 스크립트 및 데이터 (test_valve_classifier.py, test_valve_bom.csv)

🛒 구매 관리 시스템:
- 구매 관리 테이블 스키마 (08_create_purchase_tables.sql)
- 구매확정 페이지 컴포넌트 (PurchaseConfirmationPage.jsx)
- MaterialsPage에 구매확정 버튼 추가

🎯 주요 기능:
- 밸브 타입, 연결방식, 압력등급, 재질 분류
- 구매 품목 마스터, 주문 관리, 리비전 추적
- 파이프 절단손실 및 6M 단위 계산 준비

frontend/src/pages/MaterialsPage.jsx

@@ -19,6 +19,7 @@ import {
   Divider
 } from '@mui/material';
 import ArrowBackIcon from '@mui/icons-material/ArrowBack';
+import ShoppingCart from '@mui/icons-material/ShoppingCart';
 import { api } from '../api';
 
 const MaterialsPage = () => {
@@ -412,6 +413,67 @@ const MaterialsPage = () => {
           unit: 'EA',
           isLength: false
         };
+      } else if (category === 'VALVE') {
+        // VALVE: 타입 + 연결방식 + 압력등급 + 재질 + 사이즈
+        const main_nom = material.main_nom || '';
+        const valve_type = material.valve_details?.valve_type || 'VALVE';
+        const valve_subtype = material.valve_details?.valve_subtype || '';
+        const connection_method = material.valve_details?.connection_method || '';
+        const pressure_rating = material.valve_details?.pressure_rating || '';
+        const body_material = material.valve_details?.body_material || material.material_grade || '';
+        const actuator_type = material.valve_details?.actuator_type || 'MANUAL';
+        const fire_safe = material.valve_details?.fire_safe || false;
+        
+        // 밸브 스펙 생성
+        const valve_spec_parts = [];
+        
+        // 밸브 타입 (GATE_VALVE, BALL_VALVE 등)
+        if (valve_type && valve_type !== 'UNKNOWN') {
+          valve_spec_parts.push(valve_type.replace('_', ' '));
+        }
+        
+        // 연결 방식 (FLANGED, THREADED, SOCKET_WELD 등)
+        if (connection_method && connection_method !== 'UNKNOWN') {
+          valve_spec_parts.push(connection_method.replace('_', ' '));
+        }
+        
+        // 압력 등급 (150LB, 300LB 등)
+        if (pressure_rating && pressure_rating !== 'UNKNOWN') {
+          valve_spec_parts.push(pressure_rating);
+        }
+        
+        // 작동 방식 (수동이 아닌 경우만 표시)
+        if (actuator_type && actuator_type !== 'MANUAL' && actuator_type !== 'UNKNOWN') {
+          valve_spec_parts.push(actuator_type.replace('_', ' '));
+        }
+        
+        // 특수 기능 (Fire Safe 등)
+        if (fire_safe) {
+          valve_spec_parts.push('FIRE SAFE');
+        }
+        
+        if (valve_subtype && valve_subtype !== 'UNKNOWN') {
+          valve_spec_parts.push(valve_subtype);
+        }
+        
+        const full_valve_spec = valve_spec_parts.join(', ');
+        
+        specKey = `${category}|${full_valve_spec}|${body_material}|${main_nom}`;
+        specData = {
+          category: 'VALVE',
+          valve_type,
+          valve_subtype,
+          connection_method,
+          pressure_rating,
+          body_material,
+          actuator_type,
+          fire_safe,
+          full_valve_spec,
+          size_display: main_nom,
+          main_nom,
+          unit: 'EA',
+          isLength: false
+        };
       } else {
         // 기타 자재: 기본 분류
         const material_spec = material.material_grade || '';
@@ -515,14 +577,30 @@ const MaterialsPage = () => {
     <Box sx={{ maxWidth: 1400, mx: 'auto', mt: 4, px: 2 }}>
       {/* 헤더 */}
       <Box sx={{ mb: 3 }}>
-        <Button
-          variant="outlined"
-          startIcon={<ArrowBackIcon />}
-          onClick={() => navigate(-1)}
-          sx={{ mb: 2 }}
-        >
-          뒤로가기
-        </Button>
+        <Box sx={{ display: 'flex', alignItems: 'center', justifyContent: 'space-between', mb: 2 }}>
+          <Button
+            variant="outlined"
+            startIcon={<ArrowBackIcon />}
+            onClick={() => navigate(-1)}
+          >
+            뒤로가기
+          </Button>
+          
+          <Button
+            variant="contained"
+            color="success"
+            size="large"
+            startIcon={<ShoppingCart />}
+            onClick={() => {
+              const params = new URLSearchParams(window.location.search);
+              navigate(`/purchase-confirmation?${params.toString()}`);
+            }}
+            disabled={materialSpecs.length === 0}
+            sx={{ minWidth: 150 }}
+          >
+            구매 확정
+          </Button>
+        </Box>
         
         <Typography variant="h4" component="h1" gutterBottom>
           📋 자재 사양서
@@ -644,7 +722,18 @@ const MaterialsPage = () => {
                           <TableCell align="right"><strong>수량</strong></TableCell>
                         </>
                       )}
-                      {!['PIPE', 'FITTING', 'FLANGE', 'GASKET', 'BOLT', 'INSTRUMENT'].includes(category) && (
+                      {category === 'VALVE' && (
+                        <>
+                          <TableCell><strong>밸브 타입</strong></TableCell>
+                          <TableCell><strong>연결방식</strong></TableCell>
+                          <TableCell><strong>압력등급</strong></TableCell>
+                          <TableCell><strong>재질</strong></TableCell>
+                          <TableCell><strong>사이즈</strong></TableCell>
+                          <TableCell><strong>작동방식</strong></TableCell>
+                          <TableCell align="right"><strong>수량</strong></TableCell>
+                        </>
+                      )}
+                      {!['PIPE', 'FITTING', 'FLANGE', 'GASKET', 'BOLT', 'INSTRUMENT', 'VALVE'].includes(category) && (
                         <>
                           <TableCell><strong>재질</strong></TableCell>
                           <TableCell><strong>사이즈</strong></TableCell>
@@ -787,7 +876,47 @@ const MaterialsPage = () => {
                             </TableCell>
                           </>
                         )}
-                        {(!['PIPE', 'FITTING', 'FLANGE', 'GASKET', 'BOLT', 'INSTRUMENT'].includes(category)) && (
+                        {category === 'VALVE' && (
+                          <>
+                            <TableCell>
+                              <Typography variant="body2" sx={{ fontWeight: 'bold' }}>
+                                {spec.valve_type?.replace('_', ' ') || 'VALVE'}
+                              </Typography>
+                            </TableCell>
+                            <TableCell>
+                              <Typography variant="body2">
+                                {spec.connection_method?.replace('_', ' ') || 'Unknown'}
+                              </Typography>
+                            </TableCell>
+                            <TableCell>
+                              <Typography variant="body2">
+                                {spec.pressure_rating || 'Unknown'}
+                              </Typography>
+                            </TableCell>
+                            <TableCell>
+                              <Typography variant="body2">
+                                {spec.body_material || 'Unknown'}
+                              </Typography>
+                            </TableCell>
+                            <TableCell>
+                              <Typography variant="body2">
+                                {spec.size_display || 'Unknown'}
+                              </Typography>
+                            </TableCell>
+                            <TableCell>
+                              <Typography variant="body2">
+                                {spec.actuator_type?.replace('_', ' ') || 'MANUAL'}
+                                {spec.fire_safe && ' + FIRE SAFE'}
+                              </Typography>
+                            </TableCell>
+                            <TableCell align="right">
+                              <Typography variant="body2" fontWeight="bold">
+                                {spec.totalQuantity} {spec.unit}
+                              </Typography>
+                            </TableCell>
+                          </>
+                        )}
+                        {(!['PIPE', 'FITTING', 'FLANGE', 'GASKET', 'BOLT', 'INSTRUMENT', 'VALVE'].includes(category)) && (
                           <>
                             <TableCell>{spec.material_spec || 'Unknown'}</TableCell>
                             <TableCell>{spec.size_display || 'Unknown'}</TableCell>

frontend/src/pages/PurchaseConfirmationPage.jsx

@@ -0,0 +1,391 @@
+import React, { useState, useEffect } from 'react';
+import { useLocation, useNavigate } from 'react-router-dom';
+import {
+  Box,
+  Card,
+  CardContent,
+  Typography,
+  Table,
+  TableBody,
+  TableCell,
+  TableContainer,
+  TableHead,
+  TableRow,
+  Paper,
+  Button,
+  TextField,
+  Chip,
+  Alert,
+  IconButton,
+  Dialog,
+  DialogTitle,
+  DialogContent,
+  DialogActions,
+  Grid,
+  Divider
+} from '@mui/material';
+import {
+  ArrowBack,
+  Edit,
+  Check,
+  Close,
+  ShoppingCart,
+  CompareArrows,
+  Warning
+} from '@mui/icons-material';
+import { api } from '../api';
+
+const PurchaseConfirmationPage = () => {
+  const location = useLocation();
+  const navigate = useNavigate();
+  const [purchaseItems, setPurchaseItems] = useState([]);
+  const [revisionComparison, setRevisionComparison] = useState(null);
+  const [loading, setLoading] = useState(true);
+  const [editingItem, setEditingItem] = useState(null);
+  const [confirmDialog, setConfirmDialog] = useState(false);
+
+  // URL에서 job_no, revision 정보 가져오기
+  const searchParams = new URLSearchParams(location.search);
+  const jobNo = searchParams.get('job_no');
+  const revision = searchParams.get('revision');
+  const filename = searchParams.get('filename');
+  const previousRevision = searchParams.get('prev_revision');
+
+  useEffect(() => {
+    if (jobNo && revision) {
+      loadPurchaseItems();
+      if (previousRevision) {
+        loadRevisionComparison();
+      }
+    }
+  }, [jobNo, revision, previousRevision]);
+
+  const loadPurchaseItems = async () => {
+    try {
+      setLoading(true);
+      const response = await api.get('/purchase/items/calculate', {
+        params: { job_no: jobNo, revision: revision }
+      });
+      setPurchaseItems(response.data.items || []);
+    } catch (error) {
+      console.error('구매 품목 로딩 실패:', error);
+    } finally {
+      setLoading(false);
+    }
+  };
+
+  const loadRevisionComparison = async () => {
+    try {
+      const response = await api.get('/purchase/revision-diff', {
+        params: { 
+          job_no: jobNo, 
+          current_revision: revision,
+          previous_revision: previousRevision 
+        }
+      });
+      setRevisionComparison(response.data.comparison);
+    } catch (error) {
+      console.error('리비전 비교 실패:', error);
+    }
+  };
+
+  const updateItemQuantity = async (itemId, field, value) => {
+    try {
+      await api.patch(`/purchase/items/${itemId}`, {
+        [field]: parseFloat(value)
+      });
+      
+      // 로컬 상태 업데이트
+      setPurchaseItems(prev => 
+        prev.map(item => 
+          item.id === itemId 
+            ? { ...item, [field]: parseFloat(value) }
+            : item
+        )
+      );
+      
+      setEditingItem(null);
+    } catch (error) {
+      console.error('수량 업데이트 실패:', error);
+    }
+  };
+
+  const confirmPurchase = async () => {
+    try {
+      const response = await api.post('/purchase/orders/create', {
+        job_no: jobNo,
+        revision: revision,
+        items: purchaseItems.map(item => ({
+          purchase_item_id: item.id,
+          ordered_quantity: item.calculated_qty,
+          required_date: new Date(Date.now() + 30 * 24 * 60 * 60 * 1000) // 30일 후
+        }))
+      });
+
+      alert('구매 주문이 생성되었습니다!');
+      navigate('/materials', { 
+        state: { message: '구매 주문 생성 완료' }
+      });
+    } catch (error) {
+      console.error('구매 주문 생성 실패:', error);
+      alert('구매 주문 생성에 실패했습니다.');
+    }
+  };
+
+  const getCategoryColor = (category) => {
+    const colors = {
+      'PIPE': 'primary',
+      'FITTING': 'secondary',
+      'VALVE': 'success',
+      'FLANGE': 'warning',
+      'BOLT': 'info',
+      'GASKET': 'error',
+      'INSTRUMENT': 'purple'
+    };
+    return colors[category] || 'default';
+  };
+
+  const formatPipeInfo = (item) => {
+    if (item.category !== 'PIPE') return null;
+    
+    return (
+      <Box sx={{ mt: 1 }}>
+        <Typography variant="caption" color="textSecondary">
+          절단손실: {item.cutting_loss || 0}mm | 
+          구매: {item.pipes_count || 0}본 | 
+          여유분: {item.waste_length || 0}mm
+        </Typography>
+      </Box>
+    );
+  };
+
+  return (
+    <Box sx={{ p: 3 }}>
+      {/* 헤더 */}
+      <Box sx={{ display: 'flex', alignItems: 'center', mb: 3 }}>
+        <IconButton onClick={() => navigate(-1)} sx={{ mr: 2 }}>
+          <ArrowBack />
+        </IconButton>
+        <Box sx={{ flex: 1 }}>
+          <Typography variant="h4" gutterBottom>
+            🛒 구매 확정
+          </Typography>
+          <Typography variant="h6" color="primary">
+            Job: {jobNo} | {filename} | {revision}
+          </Typography>
+        </Box>
+        <Button
+          variant="contained"
+          startIcon={<ShoppingCart />}
+          onClick={() => setConfirmDialog(true)}
+          size="large"
+          disabled={purchaseItems.length === 0}
+        >
+          구매 주문 생성
+        </Button>
+      </Box>
+
+      {/* 리비전 비교 알림 */}
+      {revisionComparison && (
+        <Alert 
+          severity={revisionComparison.has_changes ? "warning" : "info"} 
+          sx={{ mb: 3 }}
+          icon={<CompareArrows />}
+        >
+          <Typography variant="body2">
+            <strong>리비전 변경사항:</strong> {revisionComparison.summary}
+          </Typography>
+          {revisionComparison.additional_items && (
+            <Typography variant="body2" sx={{ mt: 1 }}>
+              추가 구매 필요: {revisionComparison.additional_items}개 품목
+            </Typography>
+          )}
+        </Alert>
+      )}
+
+      {/* 구매 품목 테이블 */}
+      {purchaseItems.map(item => (
+        <Card key={item.id} sx={{ mb: 2 }}>
+          <CardContent>
+            <Box sx={{ display: 'flex', alignItems: 'center', mb: 2 }}>
+              <Chip 
+                label={item.category} 
+                color={getCategoryColor(item.category)}
+                sx={{ mr: 2 }}
+              />
+              <Typography variant="h6" sx={{ flex: 1 }}>
+                {item.specification}
+              </Typography>
+              {item.is_additional && (
+                <Chip 
+                  label="추가 구매" 
+                  color="warning" 
+                  variant="outlined"
+                />
+              )}
+            </Box>
+
+            <Grid container spacing={3}>
+              {/* BOM 수량 */}
+              <Grid item xs={12} md={3}>
+                <Typography variant="body2" color="textSecondary">
+                  BOM 필요량
+                </Typography>
+                <Typography variant="h6">
+                  {item.bom_quantity} {item.unit}
+                </Typography>
+                {formatPipeInfo(item)}
+              </Grid>
+
+              {/* 구매 수량 */}
+              <Grid item xs={12} md={3}>
+                <Typography variant="body2" color="textSecondary">
+                  구매 수량
+                </Typography>
+                {editingItem === item.id ? (
+                  <Box sx={{ display: 'flex', alignItems: 'center', gap: 1 }}>
+                    <TextField
+                      value={item.calculated_qty}
+                      onChange={(e) => 
+                        setPurchaseItems(prev => 
+                          prev.map(i => 
+                            i.id === item.id 
+                              ? { ...i, calculated_qty: parseFloat(e.target.value) || 0 }
+                              : i
+                          )
+                        )
+                      }
+                      size="small"
+                      type="number"
+                      sx={{ width: 100 }}
+                    />
+                    <IconButton 
+                      size="small" 
+                      color="primary"
+                      onClick={() => updateItemQuantity(item.id, 'calculated_qty', item.calculated_qty)}
+                    >
+                      <Check />
+                    </IconButton>
+                    <IconButton 
+                      size="small"
+                      onClick={() => setEditingItem(null)}
+                    >
+                      <Close />
+                    </IconButton>
+                  </Box>
+                ) : (
+                  <Box sx={{ display: 'flex', alignItems: 'center', gap: 1 }}>
+                    <Typography variant="h6" color="primary">
+                      {item.calculated_qty} {item.unit}
+                    </Typography>
+                    <IconButton 
+                      size="small"
+                      onClick={() => setEditingItem(item.id)}
+                    >
+                      <Edit />
+                    </IconButton>
+                  </Box>
+                )}
+              </Grid>
+
+              {/* 이미 구매한 수량 */}
+              {previousRevision && (
+                <Grid item xs={12} md={3}>
+                  <Typography variant="body2" color="textSecondary">
+                    기구매 수량
+                  </Typography>
+                  <Typography variant="h6">
+                    {item.purchased_quantity || 0} {item.unit}
+                  </Typography>
+                </Grid>
+              )}
+
+              {/* 추가 구매 필요량 */}
+              {previousRevision && (
+                <Grid item xs={12} md={3}>
+                  <Typography variant="body2" color="textSecondary">
+                    추가 구매 필요
+                  </Typography>
+                  <Typography 
+                    variant="h6" 
+                    color={item.additional_needed > 0 ? "error" : "success"}
+                  >
+                    {Math.max(item.additional_needed || 0, 0)} {item.unit}
+                  </Typography>
+                </Grid>
+              )}
+            </Grid>
+
+            {/* 여유율 및 최소 주문 정보 */}
+            <Box sx={{ mt: 2, p: 2, bgcolor: 'grey.50', borderRadius: 1 }}>
+              <Grid container spacing={2}>
+                <Grid item xs={6} md={3}>
+                  <Typography variant="caption" color="textSecondary">
+                    여유율
+                  </Typography>
+                  <Typography variant="body2">
+                    {((item.safety_factor || 1) - 1) * 100}%
+                  </Typography>
+                </Grid>
+                <Grid item xs={6} md={3}>
+                  <Typography variant="caption" color="textSecondary">
+                    최소 주문
+                  </Typography>
+                  <Typography variant="body2">
+                    {item.min_order_qty || 0} {item.unit}
+                  </Typography>
+                </Grid>
+                <Grid item xs={6} md={3}>
+                  <Typography variant="caption" color="textSecondary">
+                    예상 여유분
+                  </Typography>
+                  <Typography variant="body2">
+                    {(item.calculated_qty - item.bom_quantity).toFixed(1)} {item.unit}
+                  </Typography>
+                </Grid>
+                <Grid item xs={6} md={3}>
+                  <Typography variant="caption" color="textSecondary">
+                    활용률
+                  </Typography>
+                  <Typography variant="body2">
+                    {((item.bom_quantity / item.calculated_qty) * 100).toFixed(1)}%
+                  </Typography>
+                </Grid>
+              </Grid>
+            </Box>
+          </CardContent>
+        </Card>
+      ))}
+
+      {/* 구매 주문 확인 다이얼로그 */}
+      <Dialog open={confirmDialog} onClose={() => setConfirmDialog(false)}>
+        <DialogTitle>구매 주문 생성 확인</DialogTitle>
+        <DialogContent>
+          <Typography variant="body2" sx={{ mb: 2 }}>
+            총 {purchaseItems.length}개 품목에 대한 구매 주문을 생성하시겠습니까?
+          </Typography>
+          
+          {revisionComparison && revisionComparison.has_changes && (
+            <Alert severity="warning" sx={{ mb: 2 }}>
+              리비전 변경으로 인한 추가 구매가 포함되어 있습니다.
+            </Alert>
+          )}
+          
+          <Typography variant="body2" color="textSecondary">
+            구매 주문 생성 후에는 수량 변경이 제한됩니다.
+          </Typography>
+        </DialogContent>
+        <DialogActions>
+          <Button onClick={() => setConfirmDialog(false)}>
+            취소
+          </Button>
+          <Button onClick={confirmPurchase} variant="contained">
+            주문 생성
+          </Button>
+        </DialogActions>
+      </Dialog>
+    </Box>
+  );
+};
+
+export default PurchaseConfirmationPage;