Update Dependencies, Migrates to the newest Intellij Platform Api, Fixes Startup Issues

[R3TRO04]

This pull request updates the project to support newer versions of IntelliJ and Java, improves Gradle build performance and compatibility, and refactors the Ghidra facet editor for better reliability and maintainability. The most significant changes are grouped below by theme.

Platform and Build System Updates:

• Upgraded IntelliJ platform compatibility to version 2025.2 (platformVersion), changed platform type to IU, and increased supported build range (pluginUntilBuild) in gradle.properties. Also bumped pluginVersion to 0.6.0.
• Updated Java language level to 21 (javaVersion), Gradle version to 9.0.0 (gradleVersion), and enabled parallel and configuration cache features for faster builds in gradle.properties, gradle/wrapper/gradle-wrapper.properties, and settings.gradle.kts. [1] [2] [3]
• Updated Qodana linter and project JDK to use Java 21 in qodana.yml.

Gradle and Plugin Dependency Updates:

• Upgraded key plugin versions (Kotlin, changelog, IntelliJ plugin) in gradle/libs.versions.toml and switched the IntelliJ plugin ID to org.jetbrains.intellij.platform for better compatibility with the latest platform. [1] [2]

Ghidra Facet Editor Refactoring and Reliability:

• Refactored GhidraFacetConfigurationEditor to improve reliability of library attachment: now uses the project library table directly, robustly finds and attaches class/source roots, and avoids duplicate library entries. Also improved null safety and API usage throughout the editor. [1] [2] [3] [4] [5]
• Improved null safety and API usage in GhidraFacet.kt (e.g., using firstNotNullOfOrNull and explicit types). [1] [2]

Gradle Wrapper and Script Improvements:

• Updated Gradle wrapper scripts (gradlew, gradlew.bat) for Gradle 9, improved error messaging, added SPDX license headers, and fixed CLASSPATH and library execution logic for compatibility. [1] [2] [3] [4] [5] [6] [7] [8] [9]

Minor Codebase Improvements:

• Added missing import for ExecutionException in GhidraLauncherCommandLineState.kt.

These changes collectively modernize the project and improve its stability, build speed, and maintainability.

[R3TRO04]

Hey @garyttierney! could you review my changes? 😄