datafusion: support SQL execution options

[shyjsarah]

Summary

Expose SQLContext::sql_with_options so callers can apply DataFusion SQLOptions while retaining Paimon SQL routing. The existing SQLContext::sql behavior remains unchanged and uses the default options.

Changes

• Add an additive public API that accepts SQLOptions.
• Propagate the options through statements and rewritten queries delegated to DataFusion.
• Cover statement restrictions for SET/RESET, COPY, and nested COPY under EXPLAIN.

Testing

• cargo test --locked -p paimon-datafusion --test sql_context_tests test_sql_with_options_propagates -- --nocapture
• cargo check --locked -p paimon-datafusion
• cargo fmt --all -- --check
• cargo clippy --locked -p paimon-datafusion --all-targets -- -D warnings

Notes

This is an additive public API change. Existing callers of SQLContext::sql are unaffected.

[QuakeWang]

+1