[kwsantiago]

Black-box integration tests for noz, modeled on wisp's chk expected actual harness. Two tiers.

Offline tier (tests/integration_offline.sh, 15 assertions)

No relay needed; runs in the existing build job on Linux + macOS after zig build test.

• key: key public derives the secp256k1 generator pubkey; key generate emits 64-hex sec/pub.
• decode: npub/note/nsec/nprofile NIP-19 vectors; garbage exits non-zero.
• verify: round-trips a sign-only event (arg + stdin); tampered content -> id mismatch + exit 1; malformed -> exit 1.
• event sign-only embeds the author pubkey.

Relay tier (tests/integration_relay.sh + tests/integration_sync.sh, 14 assertions)

New integration CI job clones + builds wisp (pinned v0.5.3) as the relay fixture, starts two instances, and runs noz against them. The reciprocal of wisp's CI, which already uses noz as its protocol-test client.

• round-trip (11): publish then REQ by id / author / kind / #t tag; wrong-kind, future-since, past-until are empty; NIP-45 COUNT; a fetched event passes verify; NIP-11 doc has name + supported_nips.
• NIP-77 sync (3): publish to relay A, confirm absent on B, noz sync A B, confirm present on B.

Verified

CI green on all three checks: build (ubuntu + macos) with the offline tier, and the integration job (wisp built from source, relay + sync tiers 14/14).

Closes #4.