chore(landing): 랜딩 문구 변경 — 설계 플랫폼 · 교각·교대 아카이브

- 첫 화면 부제: 교량 하부구조 3D 통합모델링 → 교량 하부구조 설계 플랫폼
- 프로젝트 탐색 패널 제목: 교각·교대 설계 라이브러리 → 교각·교대 아카이브

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

랜딩페이지/landing-page.ts

@@ -38,7 +38,7 @@ const landingPanelMarkup = `
       <div class="landing-hero-copy">
         <div class="landing-title-group">
           <h1 class="landing-title">PIER <span>&amp;</span> ABUT</h1>
-          <h2 class="landing-headline">교량 하부구조 3D 통합모델링</h2>
+          <h2 class="landing-headline">교량 하부구조 설계 플랫폼</h2>
         </div>
         <div class="landing-brand-meta">
           <span class="landing-kicker"><span class="landing-status-light"></span> PIERZAINER <span class="landing-kicker-divider">/</span><span class="landing-kicker-detail">BRIDGE DESIGN STUDIO</span></span>

랜딩페이지/sample-explorer.ts

@@ -5,7 +5,7 @@ import { createSampleMap } from './sample-map';
 import './sample-explorer.css';
 export type Sample=typeof sampleProjects[number];
 export const sampleExplorerMarkup=`<aside class="sample-explorer" aria-label="기설계 교량" data-guide-target="sample">
- <header class="sample-explorer-head"><div><span>EXPLORE PROJECTS</span><h2>교각·교대 설계 라이브러리</h2></div><b>12<span> PROJECTS</span></b></header>
+ <header class="sample-explorer-head"><div><span>EXPLORE PROJECTS</span><h2>교각·교대 아카이브</h2></div><b>12<span> PROJECTS</span></b></header>
  <section class="sample-map-section"><div class="sample-section-title"><h3>설계 프로젝트 위치</h3><div class="sample-map-modes" role="group" aria-label="지도 종류"><button type="button" data-map-mode="street" aria-pressed="true">일반</button><button type="button" data-map-mode="satellite" aria-pressed="false">위성</button></div></div><div class="sample-map" aria-label="대한민국 기설계 교량 지도"><div class="sample-location"><div class="sample-location-heading"><strong>📍 <span class="sample-location-name"></span> 위치정보</strong></div><p class="sample-address"></p><dl><dt>좌표계</dt><dd class="sample-crs"></dd><dt>조사좌표</dt><dd class="sample-survey"></dd><dt>위도·경도</dt><dd class="sample-wgs84"></dd></dl><small class="sample-coordinate-basis"></small></div><div class="sample-map-tiles"></div><div class="sample-map-markers"></div><div class="sample-map-zoom"><button type="button" data-zoom="1" aria-label="지도 확대">+</button><button type="button" data-zoom="-1" aria-label="지도 축소">−</button><button type="button" data-zoom="0" aria-label="남한 중심 기본 지도">⌂</button></div><span class="sample-map-attribution"></span><span class="sample-map-error" hidden>배경지도 연결 대기 · 좌표 마커 표시</span></div></section>
  <section class="sample-selection" aria-label="선택 교량 상세"><div class="sample-section-title"><h3>하부구조 3D 미리보기</h3><span class="sample-selection-index"></span></div>
  <div class="sample-preview" role="region" aria-label="지도·지반·교각 통합 3D 미리보기"></div>