[rust][python][c++] Carry the auto increment column through the Rust schema serde

[fresh-borzoni]

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Description

The Rust Schema serde never reads or writes auto_increment_column, the key Java uses. So enable_auto_increment is silently lost on create_table, and every table the Rust client loads reports no auto-increment column which also makes the gateway's auto-increment checks in sparse_targets unreachable.

Willingness to contribute

• I'm willing to submit a PR!