This commit modernizes the oss-licenses-plugin for Gradle 9.4 compatibility and enables full support for the Gradle Build Cache.

Key issues resolved:
- Implicit Dependency Failures: Gradle 9.x enforces strict task graph validation. The redundant LicensesCleanUpTask was removed because it conflicted with generation tasks over the build directory. Standard 'clean' now handles this idiomatically.
- Plugin Validation Errors: Modernized tasks to pass 'validatePlugins' by opting into @CacheableTask and implementing property normalization with @PathSensitive.
- Technical Debt: Refactored artifact resolution to use the Lazy Provider API, addressing feedback from PR #365 and improving configuration phase performance.
- Test Matrix: Modernized E2E tests to include AGP 9.0/9.1/9.2 and enabled strict configuration cache validation across the matrix.

Closes #356, #300, #299, #246.

…solation compatible

Refactor dependency resolution so all `Project` access happens during the
configuration phase, never at task execution time. The plugin now passes
both `--configuration-cache` and `org.gradle.unsafe.isolated-projects=true`
without discarding the cache entry, while producing byte-for-byte identical
output to the previous implementation.

Approach mirrors google/play-services-plugins#365 (oss-licenses-plugin):

- `BaseAboutLibrariesTask` exposes `configToCoordinateKeys` (`@Input
  MapProperty<String, String>`) populated lazily via
  `resolutionResult.rootComponent.map {}`, encoding coordinates as plain
  strings so the value type stays config-cache serialisable.
- `pomFileMap` (`@Internal MapProperty<String, String>`) holds
  `<group:artifact:version> -> POM file path`, populated via a
  `project.provider {}` that runs `resolvePomFiles` during config-cache
  store. `pomFiles` (`@InputFiles ConfigurableFileCollection`) is derived
  from the same `MapProperty` so the heavy resolution executes exactly
  once per build, while still tracking POM content for UP-TO-DATE checks.
- `resolvePomFiles` walks every selected configuration's
  `ResolvedComponentResult` to gather coordinates (incl. platform/BOM
  dependencies), fetches direct POMs in a single detached configuration,
  then iteratively resolves parent POMs ONE AT A TIME via per-coordinate
  detached configurations. The one-at-a-time fetch is required because
  Gradle silently dedupes overlapping `group:artifact` versions inside a
  single detached configuration, which previously caused parent metadata
  loss for transitives like `guava-parent:26.0-android` vs
  `guava-parent:33.3.1-jre`.
- `MavenXpp3Reader` is used during config phase to extract `<parent>`
  coordinates so the entire parent-POM hierarchy is pre-resolved. The
  execution-time `Maven Model Builder` then loads parents from the
  pre-populated `pomFileMap` instead of an on-demand `ModelResolver` that
  needed `project.dependencies` / `project.configurations`.
- `DependencyCollector` is split into `loadDependencyCoordinates(root)`
  (config time, pure walk over the resolution tree) and
  `loadDependenciesFromCoordinates(coords, pomFileMap)` (execution time,
  pure POM parsing). A defensive `syntheticModelSource` fallback handles
  the rare case of a parent POM that could not be resolved.
- `exclusionPatterns` switches from `SetProperty<Pattern>` to
  `SetProperty<String>` because `java.util.regex.Pattern` is not
  config-cache serialisable; patterns are compiled to `Regex` once per
  `process()` invocation.
- `AboutLibrariesIdTask` reads `configurationNames` instead of the now-
  removed `variantToDependencyData` property.
- `AboutLibrariesExportComplianceTask` moves three previously class-level
  mutable `HashSet`/`HashMap` fields into `action()` locals so the task is
  side-effect-free.
- `Configuration.isTest` no longer traverses `config.hierarchy`, removing
  configuration-graph realisation from the cheap filter step.

Test coverage (37 tests / 0 failures across 6 suites):

- `OutputCorrectnessTest` (new, 13 tests): parent-POM inheritance,
  multi-version parent POM regression, BOM include/exclude with
  `includePlatform`, `compileOnly` / `runtimeOnly` / `api` collection,
  sub-project skipping, deterministic output across runs, exact-version
  pinning, exclusion-regex (incl. alternation), full-field smoke test.
- `ConfigurationCacheTest` adds: multi-version parent POM cache survival,
  end-to-end project-isolation test (`org.gradle.unsafe.isolated-projects`
  + `--configuration-cache`).
- `PerformanceTest` threshold raised to 30s for cold-daemon environments.
- All test files updated to gson 2.11.0 / slf4j 2.0.16 / jackson 2.18.2.
- `FunctionalTest` filename corrected to `aboutlibraries.json`.

End-to-end verification: `gradle exportLibraryDefinitions
--configuration-cache` with `org.gradle.unsafe.isolated-projects=true`
on a 25-library project (incl. platform BOM, compileOnly, runtimeOnly)
produces an MD5-identical 697-line JSON to the OLD implementation.

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

…solation compatible

Refactor dependency resolution so all `Project` access happens during the
configuration phase, never at task execution time. The plugin now passes
both `--configuration-cache` and `org.gradle.unsafe.isolated-projects=true`
without discarding the cache entry, while producing byte-for-byte identical
output to the previous implementation.

Approach mirrors google/play-services-plugins#365 (oss-licenses-plugin):

- `BaseAboutLibrariesTask` exposes `configToCoordinateKeys` (`@Input
  MapProperty<String, String>`) populated lazily via
  `resolutionResult.rootComponent.map {}`, encoding coordinates as plain
  strings so the value type stays config-cache serialisable.
- `pomFileMap` (`@Internal MapProperty<String, String>`) holds
  `<group:artifact:version> -> POM file path`, populated via a
  `project.provider {}` that runs `resolvePomFiles` during config-cache
  store. `pomFiles` (`@InputFiles ConfigurableFileCollection`) is derived
  from the same `MapProperty` so the heavy resolution executes exactly
  once per build, while still tracking POM content for UP-TO-DATE checks.
- `resolvePomFiles` walks every selected configuration's
  `ResolvedComponentResult` to gather coordinates (incl. platform/BOM
  dependencies), fetches direct POMs in a single detached configuration,
  then iteratively resolves parent POMs ONE AT A TIME via per-coordinate
  detached configurations. The one-at-a-time fetch is required because
  Gradle silently dedupes overlapping `group:artifact` versions inside a
  single detached configuration, which previously caused parent metadata
  loss for transitives like `guava-parent:26.0-android` vs
  `guava-parent:33.3.1-jre`.
- `MavenXpp3Reader` is used during config phase to extract `<parent>`
  coordinates so the entire parent-POM hierarchy is pre-resolved. The
  execution-time `Maven Model Builder` then loads parents from the
  pre-populated `pomFileMap` instead of an on-demand `ModelResolver` that
  needed `project.dependencies` / `project.configurations`.
- `DependencyCollector` is split into `loadDependencyCoordinates(root)`
  (config time, pure walk over the resolution tree) and
  `loadDependenciesFromCoordinates(coords, pomFileMap)` (execution time,
  pure POM parsing). A defensive `syntheticModelSource` fallback handles
  the rare case of a parent POM that could not be resolved.
- `exclusionPatterns` switches from `SetProperty<Pattern>` to
  `SetProperty<String>` because `java.util.regex.Pattern` is not
  config-cache serialisable; patterns are compiled to `Regex` once per
  `process()` invocation.
- `AboutLibrariesIdTask` reads `configurationNames` instead of the now-
  removed `variantToDependencyData` property.
- `AboutLibrariesExportComplianceTask` moves three previously class-level
  mutable `HashSet`/`HashMap` fields into `action()` locals so the task is
  side-effect-free.
- `Configuration.isTest` no longer traverses `config.hierarchy`, removing
  configuration-graph realisation from the cheap filter step.

Test coverage (37 tests / 0 failures across 6 suites):

- `OutputCorrectnessTest` (new, 13 tests): parent-POM inheritance,
  multi-version parent POM regression, BOM include/exclude with
  `includePlatform`, `compileOnly` / `runtimeOnly` / `api` collection,
  sub-project skipping, deterministic output across runs, exact-version
  pinning, exclusion-regex (incl. alternation), full-field smoke test.
- `ConfigurationCacheTest` adds: multi-version parent POM cache survival,
  end-to-end project-isolation test (`org.gradle.unsafe.isolated-projects`
  + `--configuration-cache`).
- `PerformanceTest` threshold raised to 30s for cold-daemon environments.
- All test files updated to gson 2.11.0 / slf4j 2.0.16 / jackson 2.18.2.
- `FunctionalTest` filename corrected to `aboutlibraries.json`.

End-to-end verification: `gradle exportLibraryDefinitions
--configuration-cache` with `org.gradle.unsafe.isolated-projects=true`
on a 25-library project (incl. platform BOM, compileOnly, runtimeOnly)
produces an MD5-identical 697-line JSON to the OLD implementation.

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>