feat(phase-1): scaffold ChainLightning Sceptre plugin

Build infrastructure (Gradle wrapper, shadow, Java 25), manifest, item
JSON + interactions, and ChainLightningPlugin entry with stub handler
that logs sceptre clicks. Cooldown wiring deferred to Phase 3 (real
Hytale API is getCooldown(id).setCooldownMax — not cooldown(Duration)).

gradle/wrapper/gradle-wrapper.properties

@@ -0,0 +1,7 @@
+distributionBase=GRADLE_USER_HOME
+distributionPath=wrapper/dists
+distributionUrl=https\://services.gradle.org/distributions/gradle-9.4.1-bin.zip
+networkTimeout=10000
+validateDistributionUrl=true
+zipStoreBase=GRADLE_USER_HOME
+zipStorePath=wrapper/dists