share one loadTestConfig() helper across the tests

19 test translation units each defined an identical local loadConfig().
They now include src/test/TestConfig.h, which lives off the lib/ui/app
include path like SimulationTestAccess.h.

Co-Authored-By: Claude <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01GH8ZMRY3vhxxXcaUxBqxkk

src/test/UnlockGroupTest.cpp

@@ -19,15 +19,11 @@
 #include "SimulationTestAccess.h"
 #include "StationBodyComponent.h"
 #include "UnlocksConfig.h"
+#include "TestConfig.h"
 
 namespace
 {
 
-GameConfig loadConfig()
-{
-    return ConfigLoader::loadFromDirectory(CONFIG_DIR);
-}
-
 void killEnemyStations(Simulation& sim)
 {
     sim.getAdmin().forEach<StationBodyComponent, FactionComponent, HealthComponent>(
@@ -42,7 +38,7 @@ void killEnemyStations(Simulation& sim)
 // bay together, gated to the given station level.
 GameConfig configWithSalvageGroup(int stationLevel)
 {
-    GameConfig cfg = loadConfig();
+    GameConfig cfg = loadTestConfig();
     cfg.unlocks.groups.clear();
     cfg.unlocks.groups.push_back(
         UnlockGroupDef{"salvage_operations", stationLevel, {}, {}, {"salvager"}, {"salvage_bay"}, {}});