The Node backend's migrations, runner, queries, keys and JSON, so the
same database and Valkey serve either backend. Integration tests run
Postgres and Valkey with Quarkus Dev Services, including a game row the
Node backend wrote and an unreachable Valkey.
Quarkus 3.40 on Java 25, built with the Maven wrapper. The engine is a
line-by-line port of packages/mancala.js; a parity test replays games
recorded with the TypeScript engine, including illegal moves, and
compares every board, turn, error and the game JSON.
