chore: add spotless, spotbugs, errorprone, and openrewrite

Configure static analysis and code quality tools for consistent
code formatting and automated best-practice enforcement.

Author: AlexProgrammerDE

buildSrc/build.gradle.kts

@@ -8,6 +8,7 @@ repositories {
 }
 
 dependencies {
+    implementation("com.diffplug.spotless:spotless-plugin-gradle:8.2.1")
     implementation("com.gradleup.shadow:shadow-gradle-plugin:9.3.1")
     implementation("com.github.spotbugs.snom:spotbugs-gradle-plugin:6.4.8")
     implementation("net.ltgt.errorprone:net.ltgt.errorprone.gradle.plugin:4.4.0")

buildSrc/src/main/kotlin/pc.formatting-conventions.gradle.kts

@@ -0,0 +1,11 @@
+plugins {
+    id("com.diffplug.spotless")
+}
+
+spotless {
+    java {
+        trimTrailingWhitespace()
+        leadingTabsToSpaces(2)
+        endWithNewline()
+    }
+}

buildSrc/src/main/kotlin/pc.java-conventions.gradle.kts

@@ -2,6 +2,7 @@ import com.github.spotbugs.snom.SpotBugsTask
 import org.gradle.api.tasks.SourceSetContainer
 
 plugins {
+    id("pc.formatting-conventions")
     `java-library`
     `maven-publish`
     id("net.ltgt.errorprone")