programatically change database

**Is your feature request related to a problem? Please describe.**

I change (MySQL/MariaDB) databases frequently and have come to use SQL scripts without defining an active database using the drop-down at the top bar.

What i do is:

```
@set db_name = my_current_db_name
select * from ${db_name}.table_name;
```

Works, but

- code completion won't show table names after `${db_name}.`
- can't easily delete a row from a result set by right-clocking (because, i assume, there is no active database)

**Describe the solution you'd like**

Something like @set_active_databae = ${db_name}

**Additional context**

Community Version 25.2.0.202508311659