fix: 드롭다운 z-index 수정 및 YouTubeBotDialog 커스텀 드롭다운 적용

- WordItem, ScheduleDict 드롭다운 z-index를 z-20에서 z-40으로 변경
  (테이블 헤더의 z-30보다 높게 설정하여 가려지는 문제 해결)
- YouTubeBotDialog에 커스텀 Dropdown 컴포넌트 추가
- 네이티브 select 요소를 커스텀 드롭다운으로 교체
- 시간 선택을 위한 TIME_OPTIONS (00:00~23:00) 추가

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

frontend/src/components/pc/admin/bot/YouTubeBotDialog.jsx

@@ -1,10 +1,10 @@
 /**
  * YouTube 봇 추가/수정 다이얼로그
  */
-import { useState, useEffect } from 'react';
+import { useState, useEffect, useRef } from 'react';
 import { createPortal } from 'react-dom';
 import { motion, AnimatePresence } from 'framer-motion';
-import { Youtube, Search, X, ChevronDown, ChevronUp } from 'lucide-react';
+import { Youtube, Search, X, ChevronDown, ChevronUp, Clock } from 'lucide-react';
 
 // 동기화 간격 옵션
 const INTERVAL_OPTIONS = [
@@ -27,6 +27,79 @@ const DAY_OPTIONS = [
   { value: 6, label: '토요일' },
 ];
 
+// 시간 옵션 (00:00 ~ 23:00)
+const TIME_OPTIONS = Array.from({ length: 24 }, (_, i) => ({
+  value: `${String(i).padStart(2, '0')}:00`,
+  label: `${String(i).padStart(2, '0')}:00`,
+}));
+
+/**
+ * 커스텀 드롭다운 컴포넌트
+ */
+function Dropdown({ value, options, onChange, placeholder = '선택', className = '' }) {
+  const [isOpen, setIsOpen] = useState(false);
+  const dropdownRef = useRef(null);
+
+  useEffect(() => {
+    const handleClickOutside = (event) => {
+      if (dropdownRef.current && !dropdownRef.current.contains(event.target)) {
+        setIsOpen(false);
+      }
+    };
+
+    if (isOpen) {
+      document.addEventListener('mousedown', handleClickOutside);
+    }
+    return () => document.removeEventListener('mousedown', handleClickOutside);
+  }, [isOpen]);
+
+  const selectedOption = options.find((opt) => opt.value === value);
+
+  return (
+    <div className={`relative ${className}`} ref={dropdownRef}>
+      <button
+        type="button"
+        onClick={() => setIsOpen(!isOpen)}
+        className="flex items-center gap-2 w-full px-4 py-2.5 bg-gray-100 hover:bg-gray-200 rounded-lg text-sm transition-colors justify-between"
+      >
+        <span className={selectedOption ? 'text-gray-900' : 'text-gray-400'}>
+          {selectedOption?.label || placeholder}
+        </span>
+        <ChevronDown
+          size={14}
+          className={`text-gray-400 transition-transform ${isOpen ? 'rotate-180' : ''}`}
+        />
+      </button>
+      <AnimatePresence>
+        {isOpen && (
+          <motion.div
+            initial={{ opacity: 0, y: -5 }}
+            animate={{ opacity: 1, y: 0 }}
+            exit={{ opacity: 0, y: -5 }}
+            className="absolute top-full left-0 mt-1 w-full bg-white rounded-xl shadow-lg border border-gray-200 py-1 z-50 max-h-60 overflow-y-auto"
+          >
+            {options.map((opt) => (
+              <button
+                key={opt.value}
+                type="button"
+                onClick={() => {
+                  onChange(opt.value);
+                  setIsOpen(false);
+                }}
+                className={`w-full px-4 py-2 text-left hover:bg-gray-50 transition-colors text-sm ${
+                  value === opt.value ? 'bg-red-50 text-red-600' : ''
+                }`}
+              >
+                {opt.label}
+              </button>
+            ))}
+          </motion.div>
+        )}
+      </AnimatePresence>
+    </div>
+  );
+}
+
 function YouTubeBotDialog({ isOpen, onClose, bot = null, onSubmit }) {
   const isEdit = !!bot;
 
@@ -202,17 +275,12 @@ function YouTubeBotDialog({ isOpen, onClose, bot = null, onSubmit }) {
                 <label className="block text-sm font-medium text-gray-700 mb-1.5">
                   동기화 간격
                 </label>
-                <select
+                <Dropdown
                   value={interval}
-                  onChange={(e) => setInterval(Number(e.target.value))}
-                  className="w-full px-4 py-2.5 border border-gray-200 rounded-lg focus:outline-none focus:ring-2 focus:ring-red-500/20 focus:border-red-500 bg-white"
-                >
-                  {INTERVAL_OPTIONS.map((opt) => (
-                    <option key={opt.value} value={opt.value}>
-                      {opt.label}
-                    </option>
-                  ))}
-                </select>
+                  options={INTERVAL_OPTIONS}
+                  onChange={setInterval}
+                  placeholder="간격 선택"
+                />
               </div>
 
               {/* 예정 일정 자동 생성 */}
@@ -244,25 +312,20 @@ function YouTubeBotDialog({ isOpen, onClose, bot = null, onSubmit }) {
                     <div className="grid grid-cols-2 gap-3">
                       <div>
                         <label className="block text-sm text-gray-600 mb-1">요일</label>
-                        <select
+                        <Dropdown
                           value={scheduleDayOfWeek}
-                          onChange={(e) => setScheduleDayOfWeek(Number(e.target.value))}
-                          className="w-full px-3 py-2 border border-gray-200 rounded-lg text-sm focus:outline-none focus:ring-2 focus:ring-red-500/20 focus:border-red-500 bg-white"
-                        >
-                          {DAY_OPTIONS.map((opt) => (
-                            <option key={opt.value} value={opt.value}>
-                              {opt.label}
-                            </option>
-                          ))}
-                        </select>
+                          options={DAY_OPTIONS}
+                          onChange={setScheduleDayOfWeek}
+                          placeholder="요일 선택"
+                        />
                       </div>
                       <div>
                         <label className="block text-sm text-gray-600 mb-1">시간</label>
-                        <input
-                          type="time"
+                        <Dropdown
                           value={scheduleTime}
-                          onChange={(e) => setScheduleTime(e.target.value)}
-                          className="w-full px-3 py-2 border border-gray-200 rounded-lg text-sm focus:outline-none focus:ring-2 focus:ring-red-500/20 focus:border-red-500"
+                          options={TIME_OPTIONS}
+                          onChange={setScheduleTime}
+                          placeholder="시간 선택"
                         />
                       </div>
                     </div>
@@ -285,17 +348,12 @@ function YouTubeBotDialog({ isOpen, onClose, bot = null, onSubmit }) {
                     {/* 마감 요일 */}
                     <div>
                       <label className="block text-sm text-gray-600 mb-1">마감 요일</label>
-                      <select
+                      <Dropdown
                         value={deadlineDayOfWeek}
-                        onChange={(e) => setDeadlineDayOfWeek(Number(e.target.value))}
-                        className="w-full px-3 py-2 border border-gray-200 rounded-lg text-sm focus:outline-none focus:ring-2 focus:ring-red-500/20 focus:border-red-500 bg-white"
-                      >
-                        {DAY_OPTIONS.map((opt) => (
-                          <option key={opt.value} value={opt.value}>
-                            {opt.label}
-                          </option>
-                        ))}
-                      </select>
+                        options={DAY_OPTIONS}
+                        onChange={setDeadlineDayOfWeek}
+                        placeholder="요일 선택"
+                      />
                       <p className="text-xs text-gray-400 mt-1">
                         이 요일까지 영상이 없으면 예정 일정을 삭제합니다
                       </p>

frontend/src/components/pc/admin/schedule/WordItem.jsx

@@ -126,7 +126,7 @@ function WordItem({ id, word, pos, index, onUpdate, onDelete }) {
                 initial={{ opacity: 0, y: -5 }}
                 animate={{ opacity: 1, y: 0 }}
                 exit={{ opacity: 0, y: -5 }}
-                className="absolute top-full left-0 mt-1 w-64 bg-white rounded-xl shadow-lg border border-gray-200 py-1 z-20"
+                className="absolute top-full left-0 mt-1 w-64 bg-white rounded-xl shadow-lg border border-gray-200 py-1 z-40"
               >
                 {POS_TAGS.map((tag) => (
                   <button

frontend/src/pages/pc/admin/schedules/ScheduleDict.jsx

@@ -400,7 +400,7 @@ function ScheduleDict() {
                     initial={{ opacity: 0, y: -5 }}
                     animate={{ opacity: 1, y: 0 }}
                     exit={{ opacity: 0, y: -5 }}
-                    className="absolute top-full left-0 mt-1 w-64 bg-white rounded-xl shadow-lg border border-gray-200 py-1 z-20"
+                    className="absolute top-full left-0 mt-1 w-64 bg-white rounded-xl shadow-lg border border-gray-200 py-1 z-40"
                   >
                     {POS_TAGS.map((tag) => (
                       <button
@@ -471,7 +471,7 @@ function ScheduleDict() {
                     initial={{ opacity: 0, y: -5 }}
                     animate={{ opacity: 1, y: 0 }}
                     exit={{ opacity: 0, y: -5 }}
-                    className="absolute top-full right-0 mt-1 w-48 bg-white rounded-xl shadow-lg border border-gray-200 py-1 z-20"
+                    className="absolute top-full right-0 mt-1 w-48 bg-white rounded-xl shadow-lg border border-gray-200 py-1 z-40"
                   >
                     <button
                       onClick={() => {