fix(tarot): 히어로 영상이 정적 poster img에 가려지는 z-index 충돌 해결

video와 poster img가 같은 z-index:0 + position:absolute였고 DOM 순서상
poster가 늦게 와서 video를 영원히 덮음 → 영상 재생 중이지만 안 보임.

z-index 계층 명시: poster=0 (fallback) → video=1 → overlay=2 → content=3.
video display:none 처리되면 뒤의 poster img가 자동 노출되도록 stacking 정리.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

src/pages/tarot/Tarot.css

@@ -22,15 +22,6 @@
   overflow: hidden;
 }
 
-.tarot__hero-video {
-  position: absolute;
-  inset: 0;
-  width: 100%;
-  height: 100%;
-  object-fit: cover;
-  z-index: 0;
-}
-
 .tarot__hero-poster {
   position: absolute;
   inset: 0;
@@ -40,16 +31,25 @@
   z-index: 0;
 }
 
+.tarot__hero-video {
+  position: absolute;
+  inset: 0;
+  width: 100%;
+  height: 100%;
+  object-fit: cover;
+  z-index: 1;
+}
+
 .tarot__hero-overlay {
   position: absolute;
   inset: 0;
   background: linear-gradient(180deg, rgba(15,4,40,.5), rgba(15,4,40,.85));
-  z-index: 1;
+  z-index: 2;
 }
 
 .tarot__hero-content {
   position: relative;
-  z-index: 2;
+  z-index: 3;
   padding: 60px 40px 80px;
   max-width: 1200px;
   margin: 0 auto;