Tests never exercise @{baseVersion}@ used in DEFAULT constants

## Description

Both `DEFAULT_FILE_NAME_MAPPING` and `DEFAULT_FILE_NAME_MAPPING_CLASSIFIER` use `@{baseVersion}@` in their expressions (`MappingUtils.java:72,78`). However, every test in `MappingUtilsTest.java` uses `@{version}@` in its expressions instead.

## Risk

There is no test coverage verifying that `@{baseVersion}@` resolves correctly, or documenting the behavioral difference between `baseVersion` and `version`.

## Suggestion

Add at least one test that evaluates a mapping expression containing `@{baseVersion}@` to ensure it resolves as expected.

Start by reading MappingUtils.java around lines 72 and 78, then inspect MappingUtilsTest.java and run its existing tests. Add a focused test that evaluates an expression containing @{baseVersion}@ and confirms it resolves as expected; done means the test passes and covers the previously untested default mapping behavior.

Written by the indexing model from the issue text.