feat(snapshot): refresh API video metadata; keep removed visible

入库 / 小时近新片 / 全量快照成功时以 view_detail 覆盖 title、duration、
pages、cover、bvid、up_*、pubdate 等接口字段，并照旧写七项快照。
原站失效仅标 removed，不删行、不空写元数据；列表与详情继续展示，
快照队列仍跳过 removed。

reaction_board/repository.py

@@ -410,6 +410,75 @@ class Repository:
             return [dict(row) for row in rows]
         return self.db.read(run)
 
+    def refresh_video_metadata(
+        self,
+        *,
+        aid: int,
+        bvid: str | None,
+        title: str,
+        up_mid: int | None,
+        up_name: str | None,
+        pubdate: int,
+        duration: int | None = None,
+        pages: int | None = None,
+        cover: str | None = None,
+        up_face: str | None = None,
+        now: int | None = None,
+    ) -> bool:
+        """用接口返回字段覆盖更新已有视频元数据；不改 status，空值不冲掉旧值。
+
+        入库与快照成功路径共用。视频不存在时返回 False。
+        """
+        now = self._now() if now is None else int(now)
+        aid = int(aid)
+
+        def run(conn: sqlite3.Connection) -> bool:
+            existing = conn.execute(
+                "SELECT aid FROM video WHERE aid = ?", (aid,)
+            ).fetchone()
+            if existing is None:
+                return False
+            conn.execute(
+                """
+                UPDATE video SET
+                  bvid = COALESCE(?, bvid),
+                  title = CASE
+                    WHEN ? != '' THEN ?
+                    ELSE title
+                  END,
+                  up_mid = COALESCE(?, up_mid),
+                  up_name = COALESCE(?, up_name),
+                  pubdate = CASE
+                    WHEN ? > 0 THEN ?
+                    ELSE pubdate
+                  END,
+                  duration = COALESCE(?, duration),
+                  pages = COALESCE(?, pages),
+                  cover = COALESCE(?, cover),
+                  up_face = COALESCE(?, up_face),
+                  last_sync = ?
+                WHERE aid = ?
+                """,
+                (
+                    bvid,
+                    title or "",
+                    title or "(无标题)",
+                    up_mid,
+                    up_name,
+                    int(pubdate or 0),
+                    int(pubdate or 0),
+                    None if duration is None else int(duration),
+                    None if pages is None else int(pages),
+                    cover,
+                    up_face,
+                    now,
+                    aid,
+                ),
+            )
+            return True
+
+        return self.db.write(run)
+
     def ingest_video(
         self,
         *,
@@ -430,6 +499,7 @@ class Repository:
 
         不写 B 站收藏夹、不设置 ``folder_id``；同时删除同 aid 的候选行。
         既有的 ``removed`` / ``dropped`` / ``unfaved`` 状态都会被重新激活。
+        已存在时仍以本次接口字段为准刷新元数据。
         """
         now = self._now() if now is None else int(now)
         aid = int(aid)