filterDependencies destructively mutates the caller's set via Iterator.remove()

`AbstractAnalyzeMojo.filterDependencies()` at line 568-573:

```java
for (Iterator it = artifacts.iterator(); it.hasNext(); ) {
Artifact artifact = it.next();
if (!filter.include(artifact)) {
it.remove(); // mutates the ORIGINAL set passed in
result.add(artifact);
}
}
```

This method is called multiple times on the same set with different filter arrays (lines 363-375):

```java
ignoredUsedUndeclared.addAll(filterDependencies(usedUndeclaredWithClasses.keySet(), ignoredDependencies));
ignoredUsedUndeclared.addAll(filterDependencies(usedUndeclaredWithClasses.keySet(), ignoredUsedUndeclaredDependencies));
```

After the first non-empty filter removes matching entries from `usedUndeclaredWithClasses`, the second call operates on an already-reduced set. The "Used undeclared dependencies found:" warning listing (line 392, 394) iterates `usedUndeclaredWithClasses` which has been destructively modified — entries matching `ignoredDependencies` are silently missing from the warning output.

The same pattern applies to `unusedDeclared` and `nonTestScope` (lines 367-375).

The method should either:
1. Copy the set before iterating, or
2. Build the result without removing from the input, leaving the caller responsible for subtraction

Start in AbstractAnalyzeMojo.filterDependencies() at lines 568-573, then inspect its call sites at lines 363-375 and the warning listing at lines 392-394. Verify that repeated filtering leaves the caller's sets intact and that the warning still includes dependencies matched by earlier filters.

Written by the indexing model from the issue text.