feat: add NIP-43 invite code foundation

[Anshumancanrock]

Description

Invite code infrastructure for NIP-43 relay membership.

claimCode() uses a single atomic UPDATE with WHERE guards (not expired, uses remaining) so concurrent claims on the same code are safe without transactions.

claimed_by has no FK to users so users don't exist yet at claim time.

Related Issue

NIP-43 implementation

Motivation and Context

Need a data layer for NIP-43 join/leave handlers.

How Has This Been Tested?

25 unit tests, full suite 1322 passing.

Types of changes

• Non-functional change (docs, style, minor refactor)
• Bug fix (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 change)

Checklist:

• My code follows the code style of this project.
• My change requires a change to the documentation.
• I have updated the documentation accordingly.
• I have read the CONTRIBUTING document.
• I have added tests to cover my code changes.
• I added a changeset, or this is docs-only and I added an empty changeset.
• All new and existing tests passed.

[changeset-bot]

🦋 Changeset detected

Latest commit: b2fd527

The changes in this PR will be included in the next version bump.

This PR includes changesets to release 1 package

Name	Type
nostream	Minor

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Click here if you're a maintainer who wants to add another changeset to this PR

[coveralls]

coverage: 67.195% (+0.09%) from 67.106% — feat/nip43-invite-codes into main

[Copilot]

Pull request overview

This PR introduces foundational invite-code infrastructure to support NIP-43 relay membership workflows, including a new repository for managing invite codes, schema/types to represent them, and constants/settings needed by upcoming join/leave handlers.

Changes:

• Added InviteCodeRepository with code generation, creation, lookup, atomic claim, active-code listing, and expiry cleanup methods.
• Added invite_codes database migration plus corresponding TypeScript types and repository interface.
• Extended NIP-43-related event kind/tag constants and added nip43 settings shape.

Reviewed changes

Copilot reviewed 9 out of 9 changed files in this pull request and generated 5 comments.

Show a summary per file

File	Description
test/unit/repositories/invite-code-repository.spec.ts	Adds unit tests covering the new repository behaviors and expected transformations.
src/repositories/invite-code-repository.ts	Implements invite-code persistence and atomic claiming logic over invite_codes.
src/constants/base.ts	Adds NIP-43 event kinds and tags used by relay access metadata/requests.
src/@types/settings.ts	Introduces Nip43Settings and wires it into the global Settings type.
src/@types/repositories.ts	Defines IInviteCodeRepository interface for the new repository.
src/@types/invite-code.ts	Adds InviteCode and DBInviteCode types for app/DB representations.
migrations/20260624_120000_create_nip43_invite_codes_table.js	Creates invite_codes table and adds check constraints + expiry index.
.knip.json	Ignores the new repository file in knip analysis.
.changeset/nip43-invite-codes.md	Adds a minor changeset describing the new NIP-43 invite-code foundation.

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[cameri]

I think these two fields could just be one called remaining_uses, once it gets to <= 0 the invite can no longer be used.

[Anshumancanrock]

Makes sense! I've refactored the schema and repo logic to just use remaining_uses .To preserve the "unlimited" feature cleanly, it's now nullable.

[cameri]

Thank you @Anshumancanrock !