Exclude tidb_binlog & other reserved database names out-of-box

Feature Request

Is your feature request related to a problem? Please describe:

For the database migration that we're performing, we setup DM from Aurora to TiDB first. Then after the migration, we'll revert the replication to replicate from TiDB to Aurora using drainer.

As we switch the replication direction back and forth, we hit an issue where manual changes to tidb_binlog database propagate and break the replication.

Describe the feature you'd like:

In general, any reserved database names for TiDB tools should be excluded from replication pipeline out-of-box.

For instance, in addition to tidb_binlog, I can quickly think of the following:

• dm_meta
• sync_diff_inspector
• tidb_loader

If we get a consensus on this, I think we can apply the same default rule to other replication tools too (e.g. DM).

Describe alternatives you've considered:

• Manually add tidb_binlog to the ignore-schemas configuration

Teachability, Documentation, Adoption, Migration Strategy:

N/A

Start by tracing the existing ignore-schemas configuration and replication filters for tidb_binlog. Review how the other named tool databases are handled, then add coverage showing that reserved names are excluded by default without manual configuration.