feat(core): dispatchers, scopes, and exceptions

HytaleDispatchers (World/HytaleIO/HytaleScheduled), per-key scope
registries (PlayerScopes, WorldScopes, PluginScopes) keyed by UUID
or plugin identity, and the sealed AsyncException hierarchy.
Includes unit tests against in-memory stubs.

core/build.gradle.kts

@@ -0,0 +1,19 @@
+plugins {
+    alias(libs.plugins.kotlin.jvm)
+    `java-library`
+}
+
+dependencies {
+    api(libs.kotlinx.coroutines.core)
+    api(libs.kotlinx.coroutines.jdk8)
+    api(libs.slf4j.api)
+
+    compileOnly(libs.hytale.server)
+
+    testImplementation(libs.kotlinx.coroutines.test)
+    testImplementation(libs.junit.jupiter)
+    testRuntimeOnly(libs.junit.platform.launcher)
+    testImplementation(libs.kotest.assertions)
+    testImplementation(libs.mockk)
+    testRuntimeOnly(libs.slf4j.simple)
+}