Implement NonceManager.refresh() that respects the account lock

[N-thnI]

Description

Add sequence resynchronisation that cannot race an in-flight reservation.

Problem Statement

After a failed submission or a fee bump, the cached sequence must be resynced from the network. In vero-core-engine this is vero-core-engine#183: refresh() reads and writes sequence state without taking the per-account lock, so it can clobber a reservation another caller is mid-way through using.

Proposed Changes

• Add refresh(account) to NonceManager, acquiring the same per-account lock as reserve()
• Fetch the authoritative sequence from the network inside the critical section
• Discard reservations invalidated by the refresh, and document that behaviour on the method

Technical Implementation Scaffolding

• Target Repository: vero-sdk
• Target Path: src/nonce/index.ts
• Branch Naming: feat/issue--nonce-refresh-locked
• Authority Context: Security-sensitive — transaction sequencing

Acceptance Criteria

• A refresh() running concurrently with reserve() never produces a duplicate sequence
• Test covers refresh-during-reserve
• npm test, npm run typecheck, npm run lint, and npm run build all pass

Definition of Done

• Reviewed by lead maintainer
• Pull request merged via verified status check

[bukeeastrey]

Hi maintainer, can i take this on.

[Neziahtech]

Hello,

I’d love to take this issue on. I’m a full-stack developer with experience across Drips Waves 3–7, and the GrantFox oficiall 1 and2 campaign.

My stack includes Rust, Soroban, Solidity, and TypeScript. I can deliver a clean, tested, and well-documented solution within 24 hours of assignment.

Happy to start immediately.

[grantfox-oss]

🦊 GrantFox — @Neziahtech has been assigned to this issue as part of the Third Campaign campaign!

Next steps:

1. Open a Pull Request referencing this issue (e.g., Closes #3)
2. Your PR will be reviewed by the Vero-protocol maintainers

Good luck! Track your progress on GrantFox.

[N-thnI]

Dependency note (added by maintainer): this issue builds on #1 (NonceManager core) and #2 (per-account lock primitive), which are assigned separately and not yet merged. src/nonce/ does not exist on main yet.

Please wait for #1 and #2 to land, then build on top of them. Implementing the manager yourself inside this PR will collide with the other work in this cluster — that has already happened three times here, and it's our fault for filing these together without flagging the dependency. Sorry for the confusion.

[N-thnI]

Update — unblocked. PR #6 has merged, so src/nonce/index.ts and src/nonce/lock.ts now exist on main. This issue is standalone again: rebase onto main and add only the piece described here, rather than reimplementing the manager.

Disregard the earlier dependency note.

[N-thnI]

Closing — NonceManager.refresh() with per-account locking was delivered by PR #6, which had to build it to write the concurrency tests it was assigned. Verified on main: src/nonce/index.ts:97 acquires the lock before fetching, with the vero-core-engine#183 fix noted in its doc comment.

@Neziahtech was assigned this and has work in PR #8 — see the note there; we're sorting out fair compensation rather than just closing.