Add SpotBugs and Error Prone static analysis

[Copilot]

Integrates two static analysis tools into the Gradle build to catch bugs automatically on every ./gradlew build.

Tools Added

• SpotBugs (com.github.spotbugs v6.0.9) — bytecode-level analysis; runs after classes, generates HTML reports, fails build on findings, MAX effort
• Error Prone (net.ltgt.errorprone v3.1.0) — compile-time checks via error_prone_core v2.26.1; hooks into every compileJava/compileTestJava invocation automatically

Dependencies

• errorprone 'com.google.errorprone:error_prone_core:2.26.1' — Error Prone checker rules
• compileOnly 'com.github.spotbugs:spotbugs-annotations:4.8.3' — enables @SuppressFBWarnings for intentional suppressions

Warning

Firewall rules blocked me from connecting to one or more addresses (expand for details)

I tried to connect to the following addresses, but was blocked by firewall rules:

• hub.spigotmc.org
  • Triggering command: /usr/lib/jvm/temurin-17-jdk-amd64/bin/java /usr/lib/jvm/temurin-17-jdk-amd64/bin/java --add-opens=java.base/java.util=ALL-UNNAMED --add-opens=java.base/java.lang=ALL-UNNAMED --add-opens=java.base/java.lang.invoke=ALL-UNNAMED --add-opens=java.prefs/java.util.prefs=ALL-UNNAMED --add-opens=java.base/java.nio.charset=ALL-UNNAMED --add-opens=java.base/java.net=ALL-UNNAMED --add-opens=java.base/java.util.concurrent.atomic=ALL-UNNAMED -XX:MaxMetaspaceSize=384m -XX:+HeapDumpOnOutOfMemoryError -Xms256m -Xmx512m -Dfile.encoding=UTF-8 -Duser.country -Duser.language=en -Duser.variant -cp /home/REDACTED/.gradle/wrapper/dists/gradle-8.0.2-bin/25jlreiuz6u3xu2phlpa2vv4m/gradle-8.0.2/lib/gradle-launcher-8.0.2.jar org.gradle.launcher.daemon.bootstrap.GradleDaemon 8.0.2 (dns block)
• repo.papermc.io
  • Triggering command: /usr/lib/jvm/temurin-17-jdk-amd64/bin/java /usr/lib/jvm/temurin-17-jdk-amd64/bin/java --add-opens=java.base/java.util=ALL-UNNAMED --add-opens=java.base/java.lang=ALL-UNNAMED --add-opens=java.base/java.lang.invoke=ALL-UNNAMED --add-opens=java.prefs/java.util.prefs=ALL-UNNAMED --add-opens=java.base/java.nio.charset=ALL-UNNAMED --add-opens=java.base/java.net=ALL-UNNAMED --add-opens=java.base/java.util.concurrent.atomic=ALL-UNNAMED -XX:MaxMetaspaceSize=384m -XX:+HeapDumpOnOutOfMemoryError -Xms256m -Xmx512m -Dfile.encoding=UTF-8 -Duser.country -Duser.language=en -Duser.variant -cp /home/REDACTED/.gradle/wrapper/dists/gradle-8.0.2-bin/25jlreiuz6u3xu2phlpa2vv4m/gradle-8.0.2/lib/gradle-launcher-8.0.2.jar org.gradle.launcher.daemon.bootstrap.GradleDaemon 8.0.2 (dns block)

If you need me to access, download, or install something from one of these locations, you can either:

• Configure Actions setup steps to set up my environment, which run before the firewall is enabled
• Add the appropriate URLs or hosts to the custom allowlist in this repository's Copilot coding agent settings (admins only)