Adds a [ConfigSection("Matching")] POCO carrying the
RankBattleAiFallbackThresholdSeconds tunable (default 15). Auto-picked
up by EnsureSeedDataAsync's reflection-based ConfigSection seeder.
Consumed by InProcessPairUp in a later task.
GameConfigurationJsonbTests.EnsureSeedData_writes_one_row_per_ConfigSection_with_ShippedDefaults_payload
updated to include the new Matching section in its expected keys.
Co-Authored-By: Claude Opus 4.7 <noreply@anthropic.com>
b17c802581