채널 카드 필터 UI, 캐시 초기화, 나라 필터 수정

- 채널 설명/태그 DB 컬럼 추가 및 백오피스 편집 기능
- 채널 드롭다운을 유튜브 아이콘 토글 카드로 변경 (데스크톱 최대 4개 표시, 스크롤)
- 모바일 홈탭 채널 카드 가로 스크롤
- region "나라" 값 필터 옵션에서 제외
- 관리자 캐시 초기화 버튼 및 API 추가

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

frontend/src/app/admin/page.tsx

@@ -7,6 +7,33 @@ import { useAuth } from "@/lib/auth-context";
 
 type Tab = "channels" | "videos" | "restaurants" | "users" | "daemon";
 
+function CacheFlushButton() {
+  const [flushing, setFlushing] = useState(false);
+
+  const handleFlush = async () => {
+    if (!confirm("Redis 캐시를 초기화하시겠습니까?")) return;
+    setFlushing(true);
+    try {
+      await api.flushCache();
+      alert("캐시가 초기화되었습니다.");
+    } catch (e) {
+      alert("캐시 초기화 실패: " + (e instanceof Error ? e.message : e));
+    } finally {
+      setFlushing(false);
+    }
+  };
+
+  return (
+    <button
+      onClick={handleFlush}
+      disabled={flushing}
+      className="px-3 py-1.5 text-xs bg-red-50 text-red-600 border border-red-200 rounded-lg hover:bg-red-100 disabled:opacity-50 transition-colors"
+    >
+      {flushing ? "초기화 중..." : "🗑 캐시 초기화"}
+    </button>
+  );
+}
+
 export default function AdminPage() {
   const [tab, setTab] = useState<Tab>("channels");
   const { user, isLoading } = useAuth();
@@ -38,9 +65,12 @@ export default function AdminPage() {
               <span className="px-2 py-0.5 bg-yellow-100 text-yellow-700 rounded text-xs font-medium">읽기 전용</span>
             )}
           </div>
-          <a href="/" className="text-sm text-blue-600 hover:underline">
-            &larr; 메인으로
-          </a>
+          <div className="flex items-center gap-3">
+            {isAdmin && <CacheFlushButton />}
+            <a href="/" className="text-sm text-blue-600 hover:underline">
+              &larr; 메인으로
+            </a>
+          </div>
         </div>
         <nav className="mt-3 flex gap-1">
           {(["channels", "videos", "restaurants", "users", "daemon"] as Tab[]).map((t) => (
@@ -101,6 +131,20 @@ function ChannelsPanel({ isAdmin }: { isAdmin: boolean }) {
     }
   };
 
+  const [editingChannel, setEditingChannel] = useState<string | null>(null);
+  const [editDesc, setEditDesc] = useState("");
+  const [editTags, setEditTags] = useState("");
+
+  const handleSaveChannel = async (id: string) => {
+    try {
+      await api.updateChannel(id, { description: editDesc, tags: editTags });
+      setEditingChannel(null);
+      load();
+    } catch {
+      alert("채널 수정 실패");
+    }
+  };
+
   const handleDelete = async (channelId: string, channelName: string) => {
     if (!confirm(`"${channelName}" 채널을 삭제하시겠습니까?`)) return;
     try {
@@ -164,8 +208,9 @@ function ChannelsPanel({ isAdmin }: { isAdmin: boolean }) {
               <th className="text-left px-4 py-3">채널 이름</th>
               <th className="text-left px-4 py-3">Channel ID</th>
               <th className="text-left px-4 py-3">제목 필터</th>
+              <th className="text-left px-4 py-3">설명</th>
+              <th className="text-left px-4 py-3">태그</th>
               <th className="text-right px-4 py-3">영상 수</th>
-              <th className="text-left px-4 py-3">마지막 스캔</th>
               {isAdmin && <th className="text-left px-4 py-3">액션</th>}
               <th className="text-left px-4 py-3">스캔 결과</th>
             </tr>
@@ -186,6 +231,32 @@ function ChannelsPanel({ isAdmin }: { isAdmin: boolean }) {
                     <span className="text-gray-400 text-xs">전체</span>
                   )}
                 </td>
+                <td className="px-4 py-3 text-xs">
+                  {editingChannel === ch.id ? (
+                    <input value={editDesc} onChange={(e) => setEditDesc(e.target.value)}
+                      className="border rounded px-2 py-1 text-xs w-32 bg-white text-gray-900" placeholder="설명" />
+                  ) : (
+                    <span className="text-gray-600 cursor-pointer" onClick={() => {
+                      if (!isAdmin) return;
+                      setEditingChannel(ch.id); setEditDesc(ch.description || ""); setEditTags(ch.tags || "");
+                    }}>{ch.description || <span className="text-gray-400">-</span>}</span>
+                  )}
+                </td>
+                <td className="px-4 py-3 text-xs">
+                  {editingChannel === ch.id ? (
+                    <div className="flex gap-1">
+                      <input value={editTags} onChange={(e) => setEditTags(e.target.value)}
+                        className="border rounded px-2 py-1 text-xs w-40 bg-white text-gray-900" placeholder="태그 (쉼표 구분)" />
+                      <button onClick={() => handleSaveChannel(ch.id)} className="text-blue-600 text-xs hover:underline">저장</button>
+                      <button onClick={() => setEditingChannel(null)} className="text-gray-400 text-xs hover:underline">취소</button>
+                    </div>
+                  ) : (
+                    <span className="text-gray-500 cursor-pointer" onClick={() => {
+                      if (!isAdmin) return;
+                      setEditingChannel(ch.id); setEditDesc(ch.description || ""); setEditTags(ch.tags || "");
+                    }}>{ch.tags ? ch.tags.split(",").map(t => t.trim()).join(", ") : <span className="text-gray-400">-</span>}</span>
+                  )}
+                </td>
                 <td className="px-4 py-3 text-right font-medium">
                   {ch.video_count > 0 ? (
                     <span className="px-2 py-0.5 bg-green-50 text-green-700 rounded text-xs">{ch.video_count}개</span>
@@ -193,9 +264,6 @@ function ChannelsPanel({ isAdmin }: { isAdmin: boolean }) {
                     <span className="text-gray-400 text-xs">0</span>
                   )}
                 </td>
-                <td className="px-4 py-3 text-xs text-gray-500">
-                  {ch.last_scanned_at ? ch.last_scanned_at.slice(0, 16).replace("T", " ") : "-"}
-                </td>
                 {isAdmin && <td className="px-4 py-3 flex gap-3">
                   <button
                     onClick={() => handleScan(ch.channel_id)}