fix(530-3): D03 시작 누가 — 분석 저장본 읽을 때 같이 셈(닫힌 함수 대입을 좁힘이 never 로 봄)

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

D03_PlanAnalysis/D03_PlanAnalysis_UI_Page.ts

@@ -332,6 +332,7 @@ export async function renderD03PlanAnalysis(root: HTMLElement): Promise<void> {
   async function loadAnalysis(): Promise<void> {
     try {
       analysis = await fetchPlanAnalysis(projectId, sentPoints());
+      startM = analysis.start_chainage_m;
     } catch (error) {
       analysis = null;
       showToast(`분석 저장본을 읽지 못했습니다 — ${errorText(error)}`, "error");
@@ -454,7 +455,6 @@ export async function renderD03PlanAnalysis(root: HTMLElement): Promise<void> {
     editable = !!(await fetchSessionUser())?.is_forest_service;
     if (!(await loadPoints())) return;
     await Promise.all([loadSurfaces(), loadAnalysis()]);
-    startM = analysis?.start_chainage_m ?? 0;
     refresh();
     map.fit();
     await loadBackground();