fix(x-bot): 유튜브 일정에 채널명(source_name) 추가

- createScheduleFromYoutube에서 video.channelTitle을 source_name에 저장
- Meilisearch 동기화 시에도 source_name 포함

backend/services/x-bot.js

@@ -394,11 +394,18 @@ async function createScheduleFromYoutube(video) {
   const date = formatDate(kstDate);
   const time = formatTime(kstDate);
 
-  // 일정 생성
+  // 일정 생성 (source_name에 채널명 저장)
   const [result] = await pool.query(
     `INSERT INTO schedules (title, date, time, category_id, source_url, source_name)
-     VALUES (?, ?, ?, ?, ?, NULL)`,
-    [video.title, date, time, YOUTUBE_CATEGORY_ID, video.videoUrl]
+     VALUES (?, ?, ?, ?, ?, ?)`,
+    [
+      video.title,
+      date,
+      time,
+      YOUTUBE_CATEGORY_ID,
+      video.videoUrl,
+      video.channelTitle || null,
+    ]
   );
 
   const scheduleId = result.insertId;
@@ -418,7 +425,7 @@ async function createScheduleFromYoutube(video) {
       category_id: YOUTUBE_CATEGORY_ID,
       category_name: categoryInfo[0]?.name || "",
       category_color: categoryInfo[0]?.color || "",
-      source_name: null,
+      source_name: video.channelTitle || null,
       source_url: video.videoUrl,
       members: [],
     });