feat(arithmetization): make the arithmetization directory as Go package

[ivokub]

Currently, the arithmetization provides only the R5 interpreter sources. So when downstream users in prover-ray defines a Go test (see https://github.com/LFDT-Lineth/lineth-monorepo/blob/main/prover-ray/zkcdriver/r5_test.go) pointing to arithmetization, then it may drift as it has a local zkc dependency pointing to a previous version.

This PR now starts embedding the R5 interpreter sources and defines a getter github.com/LFDT-Lineth/lineth-monorepo/arithmetization/gopkg/embedded.CompiledBinaryFile() so that we get the compiled R5 interpreter compiled using the zkc version defined in arithmetization/go.mod. When arithmetization updates the minimal requires zkc version there then it will be recursively picked up when we update the github.com/LFDT-Lineth/lineth-monorepo/arithmetization import in prover ray.

Additionally - now instead of having a custom Make target for downloading and installing zkc, we just use the go tool zkc command instead which uses the version pinned in arithmetization/go.mod. It simplifies the process a bit for developers as we remove one additional checkout/build step so that Go handles it automatically.

Also, this PR should allow us to prepare to include the predecoding of R5 binaries and elf-to-json into arithmetization directory, where it imo belongs. Right now the elf-to-json behaviour is duplicated between arithmetization/test/scripts/elf-to-json and prover-ray/backend/zkc_r5 (where the latter now broke as elf-to-json in arithmetization does predecoding as well).

This PR depends on LFDT-Lineth/zkc#2193, so don't merge before that one is.

Checklist

• I wrote new tests for my new core changes.
• I have successfully ran tests, style checker and build against my new changes locally.
• If this change is deployed to any environment (including Devnet), E2E test coverage exists or is included in this
  PR.
• I have informed the team of any breaking changes if there are any.

[Copilot]

Pull request overview

This PR turns arithmetization/ into a standalone Go module that (1) embeds the R5 interpreter sources and (2) standardizes all local/CI usage of zkc to run via the Go tool pinned in arithmetization/go.mod, reducing drift for downstream users.

Changes:

• Added a Go module under arithmetization/ and introduced a Go package that embeds the R5 interpreter sources and exposes a CompiledBinaryFile(...) helper.
• Reworked arithmetization test tooling/Make targets to use go tool zkc (and a new prepare-zkc target) instead of installing zkc onto PATH.
• Updated GitHub Actions workflows/actions and docs/scripts to align with the module-pinned zkc tooling and Go version bump.

Reviewed changes

Copilot reviewed 23 out of 24 changed files in this pull request and generated 6 comments.

Show a summary per file

File	Description
arithmetization/src/test/zkc/poseidon2/Makefile	Switches test execution to go tool zkc.
arithmetization/src/test/scripts/weekly_zkc_metrics.sh	Updates script commentary to reflect new zkc workflow.
arithmetization/src/test/scripts/README-weekly-metrics.md	Updates weekly metrics docs to use module-pinned zkc and new make targets.
arithmetization/src/test/scripts/keccak_zkc_vs_reference_speedup/main.go	Updates invocation examples to use go -C arithmetization run ....
arithmetization/src/test/README.md	Updates test docs for module-pinned zkc usage.
arithmetization/src/test/Makefile	Replaces install-zkc flow with prepare-zkc and defaults to go -C ... tool zkc.
arithmetization/src/embedded.go	Adds embedded FS for the R5 interpreter sources (src.MainDir).
arithmetization/README.md	Documents zkc as a Go tool pinned by arithmetization/go.mod.
arithmetization/Makefile	Replaces repo-clone/install logic with prepare-zkc based on Go tool pin + optional override.
arithmetization/gopkg/embedded/embedded.go	Adds embedded package that compiles embedded sources into a constraints binary file.
arithmetization/gopkg/embedded/embedded_test.go	Adds a basic compile smoke test for CompiledBinaryFile.
arithmetization/go.sum	Adds Go module dependency checksums for arithmetization module.
arithmetization/go.mod	Introduces arithmetization Go module and pins zkc via tool directive.
.github/workflows/riscv-guests-zkc-interpreter-run.yml	Updates workflow to Go 1.25.7 and prepare-zkc usage.
.github/workflows/arithmetization-zkc-riscv-check-compilation.yml	Updates inputs/docs and cache behavior for go.mod-pinned vs overridden zkc.
.github/workflows/arithmetization-weekly-zkc-metrics.yml	Bumps Go version and adjusts comments for ref resolution.
.github/workflows/arithmetization-riscv-act4-test.yml	Updates inputs/docs and cache-save rules for pinned vs overridden zkc.
.github/workflows/arithmetization-keccak-zkc-vs-reference-benchmark.yml	Updates Go version and migrates benchmark to module-pinned zkc.
.github/workflows/arithmetization-guest-programs-trace.yml	Updates inputs/docs and removes explicit “install zkc” step assumptions.
.github/workflows/arithmetization-guest-programs-exec.yml	Updates inputs/docs and removes explicit “install zkc” step assumptions.
.github/workflows/arithmetization-benchmark-zkc-native-keccak.yml	Uses pinned zkc module version as default ref and trims trailing noise.
.github/workflows/arithmetization-benchmark-zkc-interpreter.yml	Uses pinned zkc module version as default ref and trims trailing noise.
.github/actions/setup-zkc-measurement/action.yml	Switches setup action to “prepare” module-pinned zkc and export tool info.
.github/actions/setup-arithmetization-riscv/action.yml	Updates optional zkc override handling + Go version bump.

Suppressed comments (2)

arithmetization/gopkg/embedded/embedded.go:77

• Same as above: the WalkDir callback should check the incoming "err" before using d/path, otherwise errors can be masked or turn into panics.

	if err := fs.WalkDir(subFs, ".", func(path string, d fs.DirEntry, err error) error {
		// skip predecoding directory, as it contains files that are not part of
		// the main R5 interpreter source code.
		if d.IsDir() && path == predecodingDir {
			return fs.SkipDir
		}
		if d.IsDir() {
			return nil
		}

arithmetization/src/test/README.md:344

• The example command includes -q, which is documented as removed from zkc elsewhere in this repository. Removing it avoids failures when rerunning ACT4 tests manually.

go tool zkc exec -q act4/bin/logs/<test-name>.json ../../main/riscv/main.zkc

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[Copilot]

Pull request overview

Copilot reviewed 23 out of 24 changed files in this pull request and generated 1 comment.

Suppressed comments (5)

Previously missed (3) — in code that hasn't changed since the last review.

arithmetization/src/test/Makefile:249

• In vector-exec batched mode, invoking $(MAKE) zkc-exec reruns the prepare-zkc phony target (and go mod download) in a nested make, which is unnecessary overhead. Since vector-exec already depends on prepare-zkc, call $(ZKC) exec directly here.

This issue also appears on line 267 of the same file.

		$(MAKE) --no-print-directory zkc-exec ZKC_REF= JSON=$(VECTOR_JSON_FILE) > /dev/null 2> "$$err"; \

arithmetization/src/test/Makefile:453

• act4-exec runs many JSONs and currently shells out to a nested make zkc-exec per test, which re-runs the phony prepare-zkc (and go mod download) each time. Since act4-exec already depends on prepare-zkc, call $(ZKC) exec directly in the loop to avoid repeated Go module work.

		$(MAKE) --no-print-directory zkc-exec ZKC_REF= JSON="$$json" > /dev/null 2> "$$base.err"; \

arithmetization/src/test/Makefile:6

• elf-trace is defined in this Makefile but is missing from the .PHONY list, so a file named elf-trace could prevent the target from running.

.PHONY: exec debug compile elf-exec elf-debug prepare-zkc zkc-exec zkc-trace zkc-debug clean clean-all vector-build vector-json vector-exec keccak-rust-build keccak-rust-json keccak-rust-exec keccak-zig-build keccak-zig-json keccak-zig-exec blake-rust-build blake-rust-json blake-rust-exec act4-build act4-exec require-test require-src require-vector-file require-n-vectors require-vector-build-artifacts require-vector-json-mode require-json

arithmetization/src/test/README.md:220

• This README table still documents ZKC_EXEC_FLAGS defaulting to --fast -q, but the Makefile now sets ZKC_EXEC_FLAGS ?=--fast (and other docs note -q no longer exists). This is misleading for users overriding flags.

| `ZKC_EXEC_FLAGS`             | `--fast -q`                                                                            | Flags passed to `zkc exec` within `zkc-exec` and `elf-exec`                                                                                   |

arithmetization/src/test/Makefile:267

• In vector-exec per-vector mode, each loop iteration invokes a nested make zkc-exec, which re-triggers prepare-zkc (and go mod download) because it is phony. This can drastically slow large vector runs; call $(ZKC) exec directly inside the loop instead.

			$(MAKE) --no-print-directory zkc-exec ZKC_REF= JSON="$$json" > /dev/null 2> "$$err"; \