feat: support factorial, pmod, and rint expressions

[n0r0shi]

Summary

• Wire three math functions from the datafusion-spark crate (SparkFactorial, SparkPmod, SparkRint) to Comet
• Register in jni_api.rs and add serde mappings via CometScalarFunction in QueryPlanSerde.scala

Test plan

• New tests in CometMathExpressionSuite (factorial, pmod, rint) — all pass
• Spotless formatting check passes
• Rust native build passes

[andygrove]

Serde wiring and UDF registrations look correct for all three expressions.

For the tests, the SQL file framework in spark/src/test/resources/sql-tests/expressions/math/ would be a natural home for these. There are already many math expression SQL files there.

On pmod, it might be worth testing the divide-by-zero case. Spark returns null for pmod(10, 0) with integer types and NaN for floating-point types. Floating-point inputs would also be good to cover since SparkPmod supports them.

On factorial, I like the coverage of negative and boundary values. One small thing: factorial(21) is the first value that returns null due to overflow protection. It could be worth adding that as a test case.

[n0r0shi]

@andygrove Thanks for the review! I've addressed your feedback. Also merged with latest main to resolve conflicts.

[andygrove]

LGTM pending CI. Thanks @n0r0shi

[coderfender]

@andygrove , @n0r0shi there are test failures here

[coderfender]

sql-file: expressions/math/pmod.sql [parquet.enable.dictionary=false] *** FAILED *** (149 milliseconds)
  org.apache.spark.SparkException: Job aborted due to stage failure: Task 0 in stage 1871.0 failed 1 times, most recent failure: Lost task 0.0 in stage 1871.0 (TID 7089) (localhost executor driver): org.apache.comet.CometNativeException: Divide by zero error

[coderfender]

@n0r0shi , I just saw that a PR got merged (03/09/26) which fixes this error in upstream datafusion-spark crate. We might want to wait till we upgrade comet to DF53

[coderfender]

Original PR : apache/datafusion#16829
Patch (which got merged recently) : apache/datafusion#20461

[coderfender]

@n0r0shi , perhaps you could refactor your code to drop support for pmod support so that we can merge this PR and and then come back once comet is upgraded to DF53 ?

[n0r0shi]

@coderfender Sure, thank you for the advice. I have other PRs that also depend on DF 53, so I can drop pmod and update this PR for now. Thanks!

[andygrove]

CI failure:

- sql-file: expressions/math/pmod.sql [parquet.enable.dictionary=false] *** FAILED *** (107 milliseconds)
  org.apache.spark.SparkException: Job aborted due to stage failure: Task 0 in stage 1872.0 failed 1 times, most recent failure: Lost task 0.0 in stage 1872.0 (TID 7094) (localhost executor driver): org.apache.comet.CometNativeException: Divide by zero error