feat(discover): 추천 채널 카드에 '채널 이동'(유튜브 채널 새 탭) 버튼 추가

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

src/main/resources/templates/recommend.html

@@ -42,7 +42,8 @@
             .rc-thumb { width:100%; aspect-ratio:16/9; object-fit:cover; background:#000; display:block; }
             .rc-body { padding:12px; }
             .rc-ratio { display:inline-block; background:#ef4444; color:#fff; font-weight:800; font-size:0.8rem; padding:2px 8px; border-radius:999px; }
-            .rc-actions { display:flex; gap:8px; margin-top:10px; }
+            .rc-actions { display:flex; gap:8px; margin-top:10px; flex-wrap:wrap; }
+            .rc-actions .btn { text-decoration:none; }
         </style>
 
         <script th:inline="javascript">
@@ -78,6 +79,7 @@
                     +   '<div class="text-sm text-muted mt-1" style="line-height:1.4;">'+esc(c.topVideoTitle||'')+'</div>'
                     +   '<div class="rc-actions">'
                     +     '<button class="btn btn-primary px-3 py-2" onclick="register('+c.id+')"><i data-lucide="user-plus" style="width:14px;"></i> 내 채널 등록</button>'
+                    +     '<a class="btn btn-secondary px-3 py-2" href="https://www.youtube.com/channel/'+esc(c.channelId)+'" target="_blank" title="유튜브 채널로 이동"><i data-lucide="external-link" style="width:14px;"></i> 채널 이동</a>'
                     +     '<button class="btn btn-secondary px-3 py-2" onclick="exclude('+c.id+')"><i data-lucide="x" style="width:14px;"></i> 제외</button>'
                     +   '</div>'
                     + '</div></div>').join('');