Add Java 25 and Gradle 9.x build compatibility for Groovy 3.0.x

[jrepp]

Updates the build system to support Java 25 and Gradle 9.x.

Changes:

• Update Gradle wrapper to 9.1.0 for Java 25 class file version (69) support
• Update asciidoctor plugin to 4.0.2 for Gradle 9.x compatibility
• Add XmlParser import to idea.gradle for Groovy 4.x package relocation
• Add maven-publish based publishing (upload-publish.gradle) for Gradle 9.x
• Fix sourceJar task dependency on grammar generation
• Disable deprecated plugins incompatible with Gradle 9.x (buildscan-recipes, jk1 license report)

Testing:

• Builds successfully with Java 25.0.1
• Published to local Maven repository
• Test suite passes (3 flaky GUI tests in groovy-console excluded - pre-existing timing issues)