2026-March-02 - 2.7.15426

Create core test fixtures, extract shared code. (#14140)

* Setup core test fixtures

* Moves test resources to testFixtures

Moves test map resources to the testFixtures resources directory, allowing for better build organization.

Creates a utility class to encapsulate the logic for loading game data from XML files, which simplifies testing.  This class handles resource files packaged in jars.  Updates tests to use it.

* Add build docs

* Simplifies test fixture utility class

Adopts `@lombok.experimental.UtilityClass` to automatically manage the private constructor and enforce the utility class pattern, reducing boilerplate.

Extracts the "jar" protocol string into a constant for improved readability and maintainability.