Improve logging output for parallel builds

### New feature, improvement proposal

When running parallel builds, we get output such as the following:

```
[INFO] Setup done.
[INFO] use parallelThreads 8
[INFO] Building: protoc-descriptors/pom.xml
[INFO] Building: http-url-grpc-plugin/pom.xml
[INFO] Building: gh-397-jvm-plugin-commandline-args/pom.xml
[INFO] Building: java-main-empty/pom.xml
[INFO] Building: java-main/pom.xml
[INFO] Building: gh-762-additional-args/pom.xml
[INFO] Building: gh-327-non-zip-archive-handling/pom.xml
[INFO] Building: gh-172-transitive-dependency-conflicts/pom.xml
[INFO] run selector script selector.groovy
[INFO] run selector script selector.groovy
[INFO] run selector script selector.groovy
```

In this case, it is very unclear which projects the logs for running prebuild/postbuild/selector/test scripts correspond to, which can make reviewing CI logs much more difficult.

It would be good if a common prefix could be logged instead, for example:

```
[INFO] [protoc-descriptors/pom.xml] Starting build...
[INFO] [protoc-descriptors/pom.xml] Running selector.groovy
[INFO] [protoc-descriptors/pom.xml] Project is enabled.
[INFO] [protoc-descriptors/pom.xml] Running prebuild.groovy
[INFO] [protoc-descriptors/pom.xml] Invoking Maven build
[INFO] [protoc-descriptors/pom.xml] Running postbuild.groovy
[INFO] [protoc-descriptors/pom.xml] Running test.groovy
```

Start by tracing the parallel-build logging shown in the issue, especially messages for selector, prebuild, postbuild, and test scripts. Identify where each project’s log lines are emitted; done means the relevant messages consistently include the corresponding project path as a prefix, making concurrent CI output distinguishable.

Written by the indexing model from the issue text.