Support nested values and deletion vectors in batch Diff

[JingsongLi]

What changed

• Compare ROW, ARRAY, MAP, MULTISET, and VECTOR values recursively in batch incremental Diff, including nested nulls, NaNs, and signed zero. Keep primary-key ordering restricted to scalar types.
• Plan deletion-vector index manifests independently for the before and after snapshots and apply each file's bitmap through the existing key-value reader. This supports both materialized DV scans and DV merge-on-read.
• Add end-to-end read/write coverage for nested values, vectors, projections, audit-log row kinds, historical DVs, and missing DV files.

This follows Java IncrementalDiffSplitRead: compare complete logical values and read each side with its own deletion files.

Verification

• cargo test --locked -p paimon --test incremental_diff_extended_test --features fulltext,vortex (6 passed)
• cargo test --locked -p paimon --test incremental_batch_scan_test --features fulltext,vortex (39 passed)
• cargo test --locked -p paimon --lib table::table_read::tests::test_diff --features fulltext,vortex (4 passed)
• cargo clippy --locked -p paimon --all-targets --features fulltext,vortex -- -D warnings
• cargo fmt --all -- --check

[leaves12138]

LGTM. Reviewed ab209d3; no blocking issues found.

Checked recursive ROW/ARRAY/MAP/MULTISET/VECTOR value equality, null-parent handling, NaN/signed-zero semantics, full-value comparison under projection, and independent before/after deletion-vector resolution for both materialized DV and merge-on-read scans.

Local validation (default features):

• cargo test --locked -p paimon --lib: 3113 passed, 6 ignored.
• incremental_batch_scan_test: 39 passed.
• incremental_diff_extended_test: 6 passed.
• Two additional temporary regression tests passed: deeply nested ROW/ARRAY/MAP values with null/empty distinctions and key-only projection; snapshot-specific DVs across small read batches with key filtering and audit-log assertions in both DV modes.

CI has no reported failures at the time of review; some jobs are still running. Optional fulltext/vortex feature builds were not rerun locally.