TopK operator panics on Utf8 string column overflow beyond i32::MAX

When TopK operator (ORDER BY ... LIMIT k) processes Utf8 columns where combined string data of selected rows exceeds i32::MAX (~2GB), the interleave_record_batch() call panics with 'overflow' instead of returning an error. This occurs because TopKHeap::emit_with_state() builds a single RecordBatch from all k rows via one interleave_record_batch() call, and arrow-select's interleave_bytes() panics when total byte length overflows i32.

Avoid queries with ORDER BY + LIMIT that select large string columns where k rows could exceed 2GB total. Monitor datafusion.operator.memory_used for TopK operations. Consider splitting results into smaller batches or using LargeUtf8 (i64-offset) columns for very large strings. Upgrade to version with fix from PR #20494 when available.