refactor(multisig): fix requested changes

[0xisk]

Types of changes

What types of changes does your code introduce to OpenZeppelin Midnight Contracts?
Put an `` in the boxes that apply

• Bugfix (non-breaking change which fixes an issue)
• New feature (non-breaking change which adds functionality)
• Breaking change (fix or feature that would cause existing functionality to not work as expected)
• Documentation Update (if none of the other choices apply)

Fixes #???

Contracts

• ShieldedMultiSig preset
  • Validated createShieldedProposal recipient kind — rejects UnshieldedUser, preventing permanently unexecutable proposals.
  • Added module @notice/@warning documenting that contract-address signers are unreachable until C2C auth lands, with CMA-based upgrade path.
• ShieldedMultiSigV2 preset
  • Constructor now asserts thresh <= 2 to match the 2-signature execute surface.
  • Docstring threshold range corrected.
• ShieldedTreasury
  • Moved sent-total overflow check to fail-fast before sendShielded (mirrors _deposit).
  • Renamed _shieldedReceived/_shieldedSent → _received/_sent.
  • Exported ledger fields so devs can fetch state client-side for free.
• ShieldedTreasuryStateless — _send docstring synchronized with the real signature (coin, not color).
• SignerManager — _signers changed from Map<T, Boolean> to Set<T>.
• ProposalManager — ledger fields made export.

Utils

• Moved UINT128_MAX and selfAsRecipient from both treasuries into Utils.compact; consumers now import via Utils_ prefix.
• UINT128_MAX tagged with TODO to remove once a math module is available.

Tests

• New ShieldedMultiSigV2 test scaffolding: simulator + witnesses + 12 tests (threshold guard, signer registration, duplicate/non-signer rejection, deposit, views).
• Tightened SignerManagerSimulator signer type to an exported SignerSet readonly 3-tuple — compile-time enforcement of the Vector<3> contract invariant.
• New tests in createShieldedProposal for recipient-kind guard (reject UnshieldedUser, accept Contract).
• New tests in utils.test.ts for selfAsRecipient and UINT128_MAX.
• Removed redundant UINT128_MAX exposure from treasury mocks/simulators/tests (now covered in Utils).

Docs / hygiene

• Added SPDX + OZ header banners across all multisig/*.compact files.
• Normalized JSDoc: blank line between last @param and @returns in all multisig contracts.
• Fixed witness-file header typos (…Witness.ts → …Witnesses.ts) in 4 files.
• turbo.json — compact:multisig inputs corrected from src/access/**/*.compact to src/multisig/**/*.compact.

PR Checklist

• I have read the Contributing Guide
• I have added tests that prove my fix is effective or that my feature works. See GUIDELINES.md#testing for more information.
• I have added documentation for new methods or changes to existing method behavior. See GUIDELINES.md#documentation for more information.
• CI Workflows Are Passing

Further comments

If this is a relatively large or complex change, kick off the discussion by explaining why you chose the solution you did and what alternatives you considered, etc...

[coderabbitai]

Important

Review skipped

Auto reviews are disabled on base/target branches other than the default branch.

Please check the settings in the CodeRabbit UI or the .coderabbit.yaml file in this repository. To trigger a single review, invoke the @coderabbitai review command.

⚙️ Run configuration

Configuration used: Organization UI

Review profile: CHILL

Plan: Pro

Run ID: 74cb962a-8389-490a-a18a-1e3ee22befcd

You can disable this status message by setting the reviews.review_status to false in the CodeRabbit configuration file.

Use the checkbox below for a quick retry:

• 🔍 Trigger review

✨ Finishing Touches

🧪 Generate unit tests (beta)

• Create PR with unit tests
• Commit unit tests in branch refactor/add-multisig

---

_{Comment @coderabbitai help to get the list of available commands and usage tips.}