feat: add NIP-13 Proof of Work enforcement scenarios and implementation

[Mahmoud-s-Khedr]

Description

Adds integration coverage for NIP-13 Proof of Work enforcement by introducing a new Cucumber suite under test/integration/features/nip-13/.

Included coverage:

• limits.event.eventId.minLeadingZeroBits = 0 accepts events regardless of PoW.
• limits.event.eventId.minLeadingZeroBits > 0 rejects insufficient event-id PoW with exact OK reason (pow: difficulty X<Y).
• limits.event.eventId.minLeadingZeroBits > 0 accepts sufficient event-id PoW.
• limits.event.pubkey.minLeadingZeroBits > 0 rejects insufficient pubkey PoW with exact OK reason (pow: pubkey difficulty X<Y).
• limits.event.pubkey.minLeadingZeroBits > 0 accepts sufficient pubkey PoW.

Implementation details:

• Added deterministic mining helpers in step definitions for event-id and pubkey PoW targets (below / at least threshold), avoiding flaky random behavior.
• Added test-local settings override for PoW thresholds and restoration via @nip13 After hook to avoid cross-scenario leakage.
• Kept scenario content assertions stable by varying a nonce tag during event-id mining.
• Added explicit timeout for mining-heavy steps to prevent intermittent timeout failures in slower environments.

No production API/schema behavior was changed; this is test-only coverage.

Related Issue

• Closes test: integration tests for Proof of Work enforcement (NIP-13) #507

Motivation and Context

The relay already enforces PoW using limits.event.eventId.minLeadingZeroBits and limits.event.pubkey.minLeadingZeroBits, but there was no integration coverage proving real end-to-end behavior at websocket command level.

This change closes that gap by validating:

• default acceptance when PoW requirements are disabled,
• correct rejection paths and exact rejection messages when enabled,
• successful acceptance paths when PoW requirements are met.

How Has This Been Tested?

Executed in the integration docker environment to ensure DB/cache/bootstrap conditions match integration expectations:

npm run docker:integration:run -- npm run test:integration -- test/integration/features/nip-13/nip-13.feature

Result:

• 39 scenarios (39 passed)
• 226 steps (226 passed)

Also validated local type/lint during implementation:

• npm run build:check
• npm run lint -- test/integration/features/nip-13

Types of changes

• Bug fix (non-breaking change which fixes an issue)
• New feature (non-breaking change which adds functionality)

Checklist:

• My code follows the code style of this project.
• I have read the CONTRIBUTING document.
• I have added tests to cover my code changes.
• All new and existing tests passed.

[coveralls]

coverage: 68.308%. remained the same — Mahmoud-s-Khedr:integration-test-001 into cameri:main

[Copilot]

Pull request overview

Adds end-to-end integration coverage for NIP-13 Proof-of-Work enforcement by introducing a dedicated Cucumber feature suite and step definitions that deterministically mine event-id and pubkey PoW and toggle relay settings per scenario.

Changes:

• Added @nip13 Cucumber scenarios asserting accept/reject behavior and exact OK rejection reasons for event-id and pubkey PoW thresholds.
• Implemented deterministic PoW “mining” helpers in step definitions, plus per-scenario settings overrides with restoration in an After hook.
• Added a Changesets file (currently empty frontmatter).

Reviewed changes

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

File	Description
test/integration/features/nip-13/nip-13.feature.ts	New step definitions: settings overrides, deterministic PoW mining, and command/result assertions.
test/integration/features/nip-13/nip-13.feature	New @nip13 feature with scenarios covering disabled/enabled PoW for event-id and pubkey.
.changeset/old-toys-stare.md	Adds a Changesets entry (needs proper package bump + summary).

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[cameri]

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