[JingsongLi]

Purpose

Closes #1316. Related CI failure: apache/paimon#10970.

Native upsert fails when selecting non-null FixedSizeBinary(0) values, including values nested in ROW columns. Arrow's take kernel derives the zero-width result length from its null buffer; all-valid selections have no null buffer and become empty arrays. Rebuilding the selected batch then reports inconsistent column lengths.

Brief change log

• Select affected zero-width binary columns and enclosing structs by concatenating row slices, preserving row counts, order, duplicates and validity.
• Retain the existing take path for other columns and empty selections.
• Cover sliced input, empty and single-row selections, repeated/reordered rows, NULLs, sibling fields and two levels of nested structs.

Tests

• Confirmed the new Rust regression fails before the fix with the same error as the native Python CI.
• cargo test --locked -p paimon --lib --no-default-features --features storage-memory,storage-fs table_upsert::tests: 18 passed.
• Built a Python wheel from the patched source. The zero-width binary upsert matrix passed all 16 cases, including the four original CI failures.
• native_update_encoded_inputs_test.py and native_update_binary_text_test.py, filtered to upsert: 534 passed with the rebuilt native wheel.
• cargo +1.98.0 fmt --all -- --check and git diff --check passed.
• cargo +1.98.0 clippy --locked -p paimon --lib --tests -- -D warnings passed.

API and Format

No public API or storage format changes.

Documentation

Existing supported input behavior is restored; no documentation changes are required.

[leaves12138]

LGTM