fix(travel): AlbumDetail 스크롤 안 되는 문제 수정 — SwipeableView 높이 체인 + PAGE_SIZE 40

SwipeableView가 fixed overlay 안에서 flex 높이를 채우지 못해 스크롤 불가 + IntersectionObserver 미동작.
scoped CSS로 높이 체인 복원, PAGE_SIZE 20→40으로 증가.

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

src/pages/travel/AlbumDetail.css

@@ -95,8 +95,6 @@
 
 /* ── Body ── */
 .album-detail__body {
-  flex: 1;
-  overflow-y: auto;
   min-height: 0;
   padding-bottom: env(safe-area-inset-bottom, 0);
 }
@@ -155,6 +153,26 @@
   color: var(--tv-dim, rgba(232, 221, 208, 0.25));
 }
 
+/* ── SwipeableView height chain fix ──
+   AlbumDetail is a fixed flex-column overlay.
+   SwipeableView must fill the remaining space so its panel can scroll. */
+.album-detail .swipeable-view {
+  flex: 1;
+  min-height: 0;
+  display: flex;
+  flex-direction: column;
+}
+
+.album-detail .swipeable-view__track {
+  flex: 1;
+  min-height: 0;
+}
+
+.album-detail .swipeable-view__panel {
+  height: 100%;
+  overflow-y: auto;
+}
+
 /* ── Mobile ── */
 @media (max-width: 768px) {
   .album-detail__header {

src/pages/travel/useTravelData.js

@@ -3,7 +3,7 @@ import { useCallback, useEffect, useRef, useState } from 'react';
 /* ─────────────────────────────────────────────
    Constants
 ───────────────────────────────────────────── */
-const PAGE_SIZE = 20;
+const PAGE_SIZE = 40;
 const CACHE_TTL_MS = 10 * 60 * 1000; // 10 minutes
 
 /* ─────────────────────────────────────────────