feat: `hard_delete` capability does not consider the presence of non-null `_sdc_deleted_at` values generated during LOG_BASED replication

### Singer SDK Version v0.53.4 ### Is this a regression? - [ ] Yes ### Python Version 3.14 ### Bug scope Taps (catalog, state, etc.) ### Operating System Ubuntu ### Description ## Issue Summary The `hard_delete` configuration option is only implemented for full table sync and not for log based replication int the class class SQLTarget(Target). When enabled, records with `_sdc_deleted_at` set by the source tap should be physically deleted from the target table, but instead they are only being soft-deleted (the `_sdc_deleted_at` column was populated but the records remained in the table). ## Root Cause The Meltano Singer SDK's `hard_delete` functionality only applies to `ACTIVATE_VERSION` messages (version control), not to records marked as deleted by the source tap. The SDK's `delete_old_versions` method deletes old versions based on `_sdc_table_version`, but there is no built-in mechanism to delete records where `_sdc_deleted_at` is not NULL. ## Testing Most likely tap for testing would be a postgres tap that uses log replication to a database target. I was using the Meltano target-snowflake but would apply to any database target that uses the Sinker SDK for functionality and has not overrided the base class. ### Link to Slack/Linen https://meltano.slack.com/archives/C069RH0F95F/p1767900485734439