execute() returns 0 affected rows for DML — needs mssql-tds DONE token row count

[saurabh500]

Client::execute() currently returns 0 for INSERT/UPDATE/DELETE because mssql-tds does not expose row counts from DONE tokens through its public API. get_current_resultset() returns None for DML statements, so there are no result rows to count.

Upstream fix needed: mssql-tds should expose rows_affected from consume_done_token() — either as a return value from execute() or via a public method on TdsClient.

Blocked test: execute_insert_update_delete in tests/tiberius_compat.rs is #[ignore] until this is resolved.

Upstream ref: https://github.com/microsoft/mssql-rs — TdsClient::consume_done_token() already tracks done.row_count internally but the method is pub(crate).