[PyRSA]

Summary

Add regression tests for NestedUpdate count-limit configuration, verifying Rust behavior against Java Paimon.

Changes

• Cover unset default, zero, and negative limits (non-positive admits no new rows).
• Reject invalid strings and values outside the i32 range at construction time.
• Rely on existing positive-limit coverage for keyed NestedUpdate truncation.

Compatibility

• No production code changes.
• Rust max(0) clamping remains semantically equivalent to Java NestedUpdate for non-positive limits.
• CollectAgg and other options are untouched.

Testing

• nested_update_count_limit_config_matches_java_int_option: passed.
• table::aggregator::nested: 11 passed.
• cargo fmt --check: passed.
• git diff --check: passed.