feat(bot-platform): migrate BotRegistry to Redis Streams consumer group

Replace pub/sub subscribe with XREADGROUP on bot game-start stream.
Remove dual-write from EventPublisher.publishGameStart.
Consumer group: bot-platform-consumer, XACK after forwarding.
Poll loop uses emitter identity to prevent thread leak on re-registration.
Group created with '$' offset — no historical replay on first connect.

Closes NCS-101
https://knockoutwhist.youtrack.cloud/issue/NCS-101

modules/bot-platform/build.gradle.kts

@@ -73,6 +73,7 @@ dependencies {
     testImplementation(platform("org.junit:junit-bom:5.13.4"))
     testImplementation("org.junit.jupiter:junit-jupiter")
     testImplementation("io.quarkus:quarkus-junit")
+    testImplementation("io.quarkus:quarkus-junit5-mockito")
     testImplementation("io.rest-assured:rest-assured")
     testImplementation("io.quarkus:quarkus-test-security")