docs: add documentation for arithmetic_checker

[brice-stacks]

This just adds some documentation for the arithmetic checker because once a quarter I look at this file and think, "wait, what is this doing?"

[coveralls]

Coverage Report for CI Build 25824647663

Coverage decreased (-0.03%) to 85.68%

Details

• Coverage decreased (-0.03%) from the base build.
• Patch coverage: No coverable lines changed in this PR.
• 5424 coverage regressions across 102 files.

Uncovered Changes

No uncovered changes found.

Coverage Regressions

5424 previously-covered lines in 102 files lost coverage.

Top 10 Files by Coverage Loss	Lines Losing Coverage	Coverage
stackslib/src/config/mod.rs	358	69.04%
stackslib/src/chainstate/stacks/index/storage.rs	262	80.55%
stackslib/src/chainstate/stacks/miner.rs	238	83.35%
stackslib/src/net/inv/epoch2x.rs	222	79.49%
stackslib/src/chainstate/stacks/db/transactions.rs	203	97.13%
stackslib/src/net/chat.rs	202	92.95%
stackslib/src/chainstate/stacks/db/mod.rs	196	86.23%
stackslib/src/chainstate/stacks/index/trie_sql.rs	190	69.7%
stackslib/src/core/mempool.rs	170	86.87%
stackslib/src/chainstate/stacks/index/node.rs	160	87.35%

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Coverage Stats

Relevant Lines:	219691
Covered Lines:	188232
Line Coverage:	85.68%
Coverage Strength:	18845101.9 hits per line

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💛 - Coveralls

[Copilot]

Pull request overview

Adds module-level Rustdoc describing what the arithmetic checker does and why it exists (cost-function contract eligibility checks for SIP-006 cost-voting), plus a changelog fragment noting the documentation addition.

Changes:

• Document the eligibility requirements enforced by ArithmeticOnlyChecker (determinism, no side effects, boundedness, trait restrictions).
• Explain where the eligibility result is stored and how it is used by cost-voting logic.
• Add a changelog fragment for the documentation update.

Reviewed changes

Copilot reviewed 2 out of 2 changed files in this pull request and generated 1 comment.

File	Description
clarity/src/vm/analysis/arithmetic_checker/mod.rs	Adds module-level documentation describing the arithmetic checker’s purpose, constraints, and where its result is consumed.
changelog.d/arithmetic-checker.added	Adds a changelog fragment noting the documentation addition.

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[francesco-stacks]

LGTM! Only one nit: I'd remove any reference to at-block.. just because.

Note that the tests are failing, but that's due to a PR that was recently merged in develop. You just need to sync with develop

[brice-stacks]

LGTM! Only one nit: I'd remove any reference to at-block.. just because.

Done, 238d2f9.

[francesco-stacks]

lgtm!

[Copilot]

Pull request overview

Copilot reviewed 2 out of 2 changed files in this pull request and generated 2 comments.

[cylewitruk-stacks]

lgtm 👍