Support RTAS (Replace table as select)

### Is your feature request related to a problem or challenge?

In Spark DDL you can do something like:
```
CREATE OR REPLACE TABLE table
AS
SELECT * FROM ...;
```

Which is a powerful primitive. It allows for new schema and data to be assigned whilst keeping snapshot history, table UUID.

### Describe the solution you'd like

_No response_

### Willingness to contribute

I can contribute to this feature independently

Start by locating the existing Rust DDL and table-creation or replacement paths, then trace how commits preserve snapshot history and table UUIDs. Compare those paths with Spark's CREATE OR REPLACE TABLE AS SELECT behavior; done means the operation supports new schema and data while retaining the existing table identity and snapshot history.

Written by the indexing model from the issue text.