[perNyfelt]

Matrix now requires a Groovy 6 runtime, so its next releases need to signal the compatibility break. Stable modules move to their next major, while Groovy-based 0.x modules target the next minor after their last release. Existing pending minor releases are retained. All development artifact versions keep -SNAPSHOT.

Update unreleased release notes, managed versions in matrix-bom/bom.xml, the matrix-all POM, extension metadata, consumer test coordinates, and README/tutorial/cookbook references. Rename the stats migration guide for 3.0 and update its links. BOM and matrix-all become 3.0.0-SNAPSHOT; the released core API comparison baseline remains unchanged.

Set apple.awt.UIElement=true in the shared tasks.withType(Test).configureEach configuration to suppress macOS Dock icons and reduce focus stealing when test JVMs initialize AWT, including custom test tasks.

Modules and versions:

• matrix-core → 4.0.0-SNAPSHOT.
• matrix-csv, matrix-datasets, matrix-json, matrix-spreadsheet, matrix-sql, matrix-stats, and matrix-bom / matrix-all → 3.0.0-SNAPSHOT.
• Next 0.x minor after the last release: matrix-arff, matrix-avro, matrix-bigquery, matrix-charts, matrix-ggplot, matrix-groovy-ext, matrix-gsheets, matrix-jupyter, matrix-tablesaw, and matrix-xchart.
• Retain existing pending minor versions: matrix-smile at 0.3.0-SNAPSHOT, matrix-parquet at 0.8.0-SNAPSHOT, and matrix-pict at 0.7.0-SNAPSHOT.
• Keep matrix-logging at 0.1.3-SNAPSHOT: it has no Groovy or core dependency. Its documented BOM coordinate is updated.
• Shared root Gradle configuration and documentation.

Validation passed on macOS with Java 21 after the review fixes:

• ./gradlew codenarcMain :matrix-logging:checkDocumentedVersion --console=plain
• ./gradlew spotlessCheck --console=plain
• ./gradlew test -Pheadless=true --console=plain
• git diff --check
• Checked all 21 module versions against their last release and release headings, all 20 managed BOM mappings, extension metadata, and links to the renamed stats guide. Searched README, tutorial, and cookbook text for superseded development versions and corrected the identified references.
• The earlier full test run with --info confirmed all 58 logged test JVM launches received -Dapple.awt.UIElement=true.

JavaFX activation can be independent of AWT, so the property does not guarantee prevention of every possible focus change.