test(integration): add integration tests for NIP-02 contact lists

[vikashsiwach]

Description

This PR adds integration tests for NIP-02 contact lists (Kind 3), covering replaceable event behavior.

Related Issue

Closes issue #509

Motivation and Context

Currently there were no integration tests for NIP-02 contact list(Kind 3). These tests ensure contact list updates, replacement semantics, and subscription behavior work correctly in practice.

How Has This Been Tested?

• Integration tests were added under test/integration/features/nip-02/
• All NIP-02 scenarios pass successfully.
  • Contact list event is stored and retrievable.
  • New Contact list replaces the previous one.
  • Tie-breaker logic for identical timestamps.
  • Subscribers only receive latest contact list event.

Screenshots (if appropriate):

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.

[coveralls]

coverage: 74.365% (-0.02%) from 74.382% — vikashsiwach:test/nip02-contact-list-integration into cameri:main

[Copilot]

Pull request overview

Adds end-to-end Cucumber integration coverage for NIP-02 contact list (kind 3) behavior, ensuring replaceable semantics work correctly through the relay’s WebSocket interface.

Changes:

• Introduces new NIP-02 feature scenarios covering creation, replacement, identical-timestamp tie-breaker, and subscriber behavior.
• Adds step definitions to publish kind 3 events with p tags and assert query/subscription results (including EOSE).
• Includes a Changesets patch entry documenting the test addition.

Reviewed changes

Copilot reviewed 3 out of 3 changed files in this pull request and generated 2 comments.

File	Description
test/integration/features/nip-02/nip-02.feature.ts	Adds Cucumber step definitions for publishing and asserting kind 3 contact list behavior, including replacement and tie-breaker cases.
test/integration/features/nip-02/nip-02.feature	Adds NIP-02 Gherkin scenarios for contact list storage/replacement/subscription semantics.
.changeset/nip-02-integration-tests.md	Records the test addition as a patch changeset.

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[vikashsiwach]

@cameri, I removed the unused state and updated the variable name.