Transmission #068: World WebSocket integration test

The server-authoritative overworld work needed a Docker-backed integration test for the second Tyrus channel, not just unit smoke on an embedded server.

CharacterWorldWsIntegrationTest (integration source set) now exercises the full stack from make integration-environment-setup:

• connect_receivesWorldSnapshot — single client to /v1/characters/{id}/world gets an initial worldSnapshot.
• twoClients_seeEachOther_andSharedMobKill — two WebSocket clients, reportPresence at shared GPS coords, second client’s snapshot includes the first player, server-spawned mob in worldDelta, shared combatResult on kill, and world_entity row removed after death.

Helpers mirror the events WS test: Tyrus CollectingClient is public (Java 25), JDBC via DB_URL defaults, and ApiUtils.worldWebSocketUri centralizes the ws://localhost:8080 path used by Compose.

Combat assertions move the attacker onto the mob’s reported coordinates before combatIntent — mobs spawn ~20 m outside player melee range, so standing at the harvest point alone never lands a hit. That keeps the test honest about range checks without changing spawn tuning.

All integrationTest targets pass against the published server image + Postgres stack (same path as server-ci.yml).