Brand()'s ordering by record key was only exercised indirectly, through
a test that gives each candidate product a different maker. Add a test
with two FactionProductData for the same maker and same design, distinct
record keys, asserting Brand returns the one first in record-key order.
Add the corresponding mutant (OrderBy -> OrderByDescending at Brand's
ordering) to mutation_tests.py so a regression there gets caught.
Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>
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