chore(spin-java-module, spin-junit-module): unify detect resolution

[deer]

AbstractDetectTestResolution used to duplicate the entire AbstractDetectResolution algorithm just to override two protected hook methods (additionalSiblingCandidates() and additionalArtifacts()) for TEST-scope resolutions, keeping the main-vs-test specialization at the Java subclassing level.

This replaces that with a DI-driven approach. Plugin gains a new default method, contributeBindings(Binder), invoked by DefaultProgram once per Task context before the task is instantiated, so contributed bindings are visible to its injection points. AbstractJavaPlugin and AbstractJUnitPlugin now each provide a SourcePathKind-typed scope() via @Provides (MAIN vs TEST), and AbstractJUnitPlugin uses contributeBindings to multibind the JUnit Platform ConsoleLauncher and Jupiter engine artifacts into a Set<Artifact> that AbstractDetectResolution injects directly as additionalInfrastructureArtifacts. AbstractDetectResolution.create() now gates the TEST-only sibling-main-output lookup on the injected scope field instead of delegating to an overridable hook.

AbstractDetectTestResolution is deleted; its static helpers (jupiterVersion, jupiterMajorVersion, derivePlatformVersion) move onto AbstractJUnitPlugin, and Java25JUnitPlugin/Java8JUnitPlugin's DetectTestResolution inner classes now extend AbstractDetectResolution directly, matching how the main-scope compiler plugins already worked.

This is scoped to the detect-resolution merge only. The related "main/"/"test/" build-output-prefix literals still duplicated across the Compile tasks and both ResourcePlugins, and CleanPlugin's lack of any main/test/generated distinction, are deliberately out of scope here and left for a follow-up -- the SourcePathKind @Provides wiring added in this change is meant to be the reusable foundation for that follow-up.