test: integration tests for NIP-02 contact lists (Kind 3)

[phoenix-server]

Summary

NIP-02 contact lists use kind 3, which is a replaceable event under NIP-16. While NIP-16 replaceable event semantics are already tested generically, there are no integration tests confirming the specific contact list / follow list use case works end-to-end.

What to test

• Alice publishes a kind 3 event (contact list) → stored and retrievable
• Alice publishes a second kind 3 event (updated contact list) → replaces the first; only the latest is returned by REQ
• Tie-breaker: two kind 3 events with identical timestamps → only the one with the lower event ID is kept
• Bob subscribes to Alice's kind 3 events → receives her latest contact list

Relevant code

• src/constants/base.ts — EventKinds.CONTACT_LIST
• src/handlers/event-strategies/replaceable-event-strategy.ts

Suggested location

test/integration/features/nip-02/nip-02.feature

[vikashsiwach]

@phoenix-server assign this task to me.