test: add cinematic Node smoke test

[Eth-Interchained]

Summary

Adds the missing test/smoke.mjs referenced by the existing package.json test script.

This smoke test is intentionally cinematic: it demonstrates NEDB through a rideshare incident story while asserting real behavior from the Node API:

• real NedbCore writes
• returned _hash metadata
• NQL query ordering
• verify() and head() integrity
• getAsOf() time travel using stored _seq
• durable reopen with preserved Merkle head
• graph links plus neighborsAsOf()

Local verification

I installed the published npm package in a clean temp project and ran the same suite against it:

1..5
# tests 5
# suites 0
# pass 5
# fail 0
# cancelled 0
# skipped 0
# todo 0

Note: the first draft assumed db.seq() was the stored write sequence. The real npm package showed the safer assertion is against returned/stored _seq, so this test now uses _seq for getAsOf() and graph edge boundaries.