fix(structure): B06 목록에서 고른 줄을 다시 눌러 풀면 횡단 카드 선택도 함께 풂(54-8)

- 목록 재클릭 풂 전용 알림 onListRelease 추가 — 폼 리셋·종류 바꿈 등 다른 null 고름 길은 그대로
- B06 은 그 알림에 카드 선택 풂(focusStation(null)) 연결
- 53-2 list 단계에 풂 뒤 카드 선택 0 판정 추가

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_015KYZ2HWWdUwZWYnn3tQz7X

A00_Common/design/design_shared.ts

@@ -190,6 +190,7 @@ export function sharedStructures(shared: DesignPageShared): StructuresSection {
       onPipeUpdate: (from, to, attributes) => on().onPipeUpdate?.(from, to, attributes),
       onPipeRemove: (chainageM) => on().onPipeRemove?.(chainageM),
       onPipeSelect: (chainageM) => on().onPipeSelect?.(chainageM),
+      onListRelease: () => on().onListRelease?.(),
       onReveal: () => shared.revealLeft(),
     },
     { includeDetail: () => shared.view() === "cross", projectId: shared.projectId },

A00_Common/design/design_view_cross.ts

@@ -179,6 +179,7 @@ export async function mountCrossView(
     focusChainage: (chainageM) => {
       if (!isWallSelecting()) focusStationAt(chainageM);
     },
+    releaseCard: () => sectionView.focusStation(null),
     markStructure: (structureId) => sectionView.selectMark(structureId),
     applyPipeOptions: (chainageM, patch) =>
       applyPipeOptionsToCache(pipeOptionsContext, chainageM, patch),