Prune Iceberg data files by partition values within a manifest

[osipovartem]

Summary

• Project safe Iceberg partition predicates onto each data file after manifest selection. This avoids opening unrelated files that share a manifest, while retaining old-spec, unknown-partition, and delete files.
• Fold exact cast literals before partition projection; refuse sub-microsecond timestamp values.

Validation

• cargo +1.97.0 test -p datafusion_iceberg pruning_statistics::tests --lib: 32 passed.
• cargo +1.97.0 fmt --all --check and git diff --check: passed.
• Independent read-only review approved correctness, regressions, performance, API compatibility, and focused test coverage.

The downstream Rustice test measures a five-file year-partition table with a single manifest. File pruning is asserted for microsecond-precision timestamp predicates; default-precision timestamp coercion remains a separate planner follow-up.