feat: implement core backend for team owner management with SQLite, auto-add APIs, and a frontend owner list component.

backend/internal/database/sqlite.go

@@ -189,7 +189,8 @@ func (d *DB) GetTeamOwners(status string, limit, offset int) ([]TeamOwner, int,
 		return nil, 0, err
 	}
 
-	query += " ORDER BY created_at DESC LIMIT ? OFFSET ?"
+	// 排序：已使用(used, pooled)排前面，其次按创建时间降序
+	query += " ORDER BY CASE WHEN status IN ('used', 'pooled') THEN 0 ELSE 1 END, created_at DESC LIMIT ? OFFSET ?"
 	args = append(args, limit, offset)
 
 	rows, err := d.db.Query(query, args...)
@@ -277,6 +278,15 @@ func (d *DB) ClearTeamOwners() error {
 	return err
 }
 
+// ClearUsedOwners 清理已使用的母号（status = 'used' 或 'pooled'）
+func (d *DB) ClearUsedOwners() (int64, error) {
+	result, err := d.db.Exec("DELETE FROM team_owners WHERE status IN ('used', 'pooled')")
+	if err != nil {
+		return 0, err
+	}
+	return result.RowsAffected()
+}
+
 // GetOwnersWithoutAccountID 获取缺少 account_id 的 owners
 func (d *DB) GetOwnersWithoutAccountID() ([]TeamOwner, error) {
 	rows, err := d.db.Query(`