Broaden cuDF temporal comparison coverage - #1447

Closes #1446.

Summary

• Factor the existing Temporal7 and literal/constructor temporal comparison cases so pandas and cuDF coverage share the same case data.
• Add cuDF execution for all 13 Direct-Cypher temporal comparison cases with cuDF input/output assertions and Arrow-safe result assertions.
• Add pandas/cuDF temporal property ORDER BY coverage for date, time, and datetime node columns.
• Add changelog entry under Internal.

Validation

• python3 -m pytest -q graphistry/tests/compute/gfql/cypher/test_lowering.py -k "temporal" → 63 passed, 16 skipped, 971 deselected
• git diff --check
• DGX RAPIDS 26.02: docker/test-rapids-official-local.sh focused target → 19 passed
• DGX RAPIDS 25.02: docker/test-rapids-official-local.sh focused target → 19 passed
• Review skill converged after 3 waves; final report local-only in plans/issue-1446-cudf-temporal-coverage/review/final-report.md