When shadowing one database (--dbname postgres) of a cluster that has other databases with any write activity, the daemon fatally exits

[harshil-goel]

The foreign DB 16384 is ubi_admin — the database ubicloud itself creates on every managed PG (for admin/monitoring). It has background write activity, and since physical WAL is cluster-wide, walshadow decodes those ubi_admin records, can't resolve them against its single shadow DB (postgres), and fatally crashes.

[serprex]

fixed in #73