feat(pdf-import): 외곽선 기하 후처리(축정렬 스냅·단순화·자기교차 복구) 추가

- normalizeGeometry 단계 신설: snapNearAxisEdges(축정렬 스냅) → turf.simplify(과다 정점 단순화) → cleanSelfIntersectingPolygon(자기교차 복구)
- applyOuterline의 중복점 제거 직후·fitAndCenter 전에 삽입(스냅→단순화 순서로 축정렬 보존)
- 기존 검증 순수함수 재사용, 신규 의존성 없음

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

src/hooks/pdf-import/usePdfImport.js

@@ -7,10 +7,14 @@ import { usePolygon } from '@/hooks/usePolygon'
 import { useSwal } from '@/hooks/useSwal'
 import { useMessage } from '@/hooks/useMessage'
 import { logger } from '@/util/logger'
+import { snapNearAxisEdges, cleanSelfIntersectingPolygon } from '@/util/qpolygon-utils'
+import * as turf from '@turf/turf'
 
 const MM_PER_CANVAS_UNIT = 10
 const MAX_DIM = 1500
 const MIN_CANVAS_UNIT_LENGTH = 0.5
+const SIMPLIFY_TOLERANCE = 0.5 // canvas unit ≈ 5mm. 직선 위 잉여 정점/미세 엣지 제거(보수적)
+const SNAP_ANGLE_TOL_DEG = 2 // 거의 수평/수직 엣지를 정확히 축정렬로 스냅
 
 const toCanvasUnits = (mmPoints) => mmPoints.map((p) => ({ x: p.x / MM_PER_CANVAS_UNIT, y: p.y / MM_PER_CANVAS_UNIT }))
 
@@ -57,6 +61,30 @@ const fitAndCenter = (points, canvas) => {
   }))
 }
 
+const simplifyRing = (points, tolerance) => {
+  if (points.length < 4) return points
+  try {
+    const coords = points.map((p) => [p.x, p.y])
+    coords.push([points[0].x, points[0].y])
+    const simplified = turf.simplify(turf.polygon([coords]), { tolerance, highQuality: true })
+    const ring = simplified.geometry.coordinates[0]
+    const out = ring.slice(0, -1).map((c) => ({ x: c[0], y: c[1] }))
+    return out.length >= 3 ? out : points
+  } catch (e) {
+    logger.warn('[usePdfImport] simplifyRing 실패', e?.message || e)
+    return points
+  }
+}
+
+// AI 추출 좌표의 결정적 정규화: 축정렬 스냅 → 과다정점 단순화 → 자기교차 복구.
+// 순서 주의 — 스냅(정점 이동) 후 단순화(정점 제거)해야 축정렬이 보존된다.
+const normalizeGeometry = (points) => {
+  let pts = snapNearAxisEdges(points, SNAP_ANGLE_TOL_DEG)
+  pts = simplifyRing(pts, SIMPLIFY_TOLERANCE)
+  pts = cleanSelfIntersectingPolygon(pts)
+  return pts.length >= 3 ? pts : points
+}
+
 export function usePdfImport() {
   const canvas = useRecoilValue(canvasState)
   const setOuterLinePoints = useSetRecoilState(outerLinePointsState)
@@ -133,6 +161,7 @@ export function usePdfImport() {
       return false
     }
 
+    canvasPoints = normalizeGeometry(canvasPoints)
     canvasPoints = fitAndCenter(canvasPoints, canvas)
     canvasPoints = ensureCounterClockwise(canvasPoints)