feat: implement log-derivative argument over small fields

[ivokub]

Description

We previously didn't support doing log-derivative argument over small fields as we didn't have operations for defining the log-derivative argument. But now with #1672 we can complete the implementation.

This particularly allows for lookups, range checks etc.

NB! Merge only after #1672.

Type of change

• New feature (non-breaking change which adds functionality)

How has this been tested?

• added explicit small field check for range check and logderivprecomp tests.

Checklist:

• I have performed a self-review of my code
• I have commented my code, particularly in hard-to-understand areas
• I have made corresponding changes to the documentation
• I have added tests that prove my fix is effective or that my feature works
• I did not modify files generated from templates
• golangci-lint does not output errors locally
• New and existing unit tests pass locally with my changes
• Any dependent changes have been merged and published in downstream modules

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Note

Enables the log-derivative argument on small fields and aligns range checking to work with wide commitments.

• Implement small-field path in logderivarg.Build: use fieldextension ops and multicommit.WithWideCommitment; add extension-based coefficient/combination helpers and small-field detection via smallfields.IsSmallField
• Preserve existing large-field path with WithCommitment and batch inversion where available
• Update rangecheck.New to return newCommitRangechecker for frontend.WideCommitter (remove panic)
• Tests: add test.WithSmallfieldCheck() to lookup; rework rangecheck tests (smaller samples, explicit invalid assignments, add small-field variant)

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[Copilot]

Pull request overview

This PR implements log-derivative argument support for small fields (BabyBear, KoalaBear, Goldilocks) by utilizing field extensions and the WithWideCommitment interface. Previously, attempting to use range checking with small fields would panic; this change enables it for single-column tables.

Key changes:

• Enables log-derivative arguments over small fields using field extensions
• Adds small field test coverage for range checking
• Removes panic for WideCommitter in rangecheck package

Reviewed changes

Copilot reviewed 3 out of 3 changed files in this pull request and generated 3 comments.

File	Description
std/rangecheck/rangecheck.go	Removes panic for WideCommitter case and enables commit-based range checking for small fields
std/rangecheck/rangecheck_test.go	Refactors test to use CheckCircuit helper, reduces test size, and adds dedicated small field test
std/internal/logderivarg/logderivarg.go	Implements small field support using field extensions and WithWideCommitment, but only for single-column tables

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