EffectivePomMojo.cleanModel() mutates the live project Model in-place

In src/main/java/org/apache/maven/plugins/help/EffectivePomMojo.java:210-213:

private static void cleanModel(Model pom) {
Properties properties = new SortedProperties();
properties.putAll(pom.getProperties());
pom.setProperties(properties);
}

Called from writeEffectivePom() at line 182 on project.getModel(). This permanently replaces the project Properties with a SortedProperties instance, altering property iteration order for the remainder of the build. This is a data corruption side effect in what should be a read-only display operation.

Start in src/main/java/org/apache/maven/plugins/help/EffectivePomMojo.java by reading writeEffectivePom() around line 182 and cleanModel() around lines 210-213. Verify that generating the effective POM no longer changes project.getModel().getProperties() or its iteration order, and run the relevant project tests to confirm the display operation remains correct.

Written by the indexing model from the issue text.