dependency:tree -Dscope filter is silently non-functional due to MSHARED-4

`TreeMojo` has a `scope` parameter (line 122) that is supposed to filter the dependency tree, but it has been non-functional for years due to `MSHARED-4` in the `maven-dependency-tree` library. The TODO at line 232 documents this:

```java
// TODO: note that filter does not get applied due to MSHARED-4
ArtifactFilter artifactFilter = createResolvingArtifactFilter();
```

The `artifactFilter` is passed to `dependencyCollectorBuilder.collectDependencyGraph()` and `dependencyGraphBuilder.buildDependencyGraph()` at lines 241 and 246, but these methods ignore the filter. This means:

```bash
mvn dependency:tree -Dscope=compile
```

still shows all scopes (test, provided, etc.) with no warning that the filter was not applied.

The fix would be to apply the filter client-side after obtaining the tree, or to fix MSHARED-4 in maven-dependency-tree, or at minimum to log a warning when a scope is specified that it may not be honored.

Start in TreeMojo around the scope parameter and the TODO near line 232, then trace createResolvingArtifactFilter through dependencyCollectorBuilder.collectDependencyGraph() and dependencyGraphBuilder.buildDependencyGraph() at lines 241 and 246. Reproduce with mvn dependency:tree -Dscope=compile and verify that the chosen resolution either honors the scope filter or clearly warns when it cannot be applied.

Written by the indexing model from the issue text.