allow to configure when which schematic gets unlockable

src/test/BlueprintTest.cpp

@@ -654,7 +654,7 @@ TEST_CASE("Blueprint placement: recipe transfers to building after construction
 
 TEST_CASE("Blueprint placement: interceptor schematic is unlocked at game start", "[blueprint]")
 {
-    // "interceptor" has available_from_start = true in the test config.
+    // "interceptor" has unlock_at_station_level = -1 in the test config.
     // This confirms the guard in placeBlueprintAtTile passes for start-unlocked schematics.
     Simulation sim(loadConfig());
     REQUIRE(sim.isSchematicUnlocked("interceptor"));
@@ -662,7 +662,7 @@ TEST_CASE("Blueprint placement: interceptor schematic is unlocked at game start"
 
 TEST_CASE("Blueprint placement: repair_ship schematic is locked at game start", "[blueprint]")
 {
-    // "repair_ship" has available_from_start = false in the test config.
+    // "repair_ship" has unlock_at_station_level = 0 in the test config.
     // This confirms the guard in placeBlueprintAtTile blocks locked schematics,
     // leaving the shipyard's schematic unset.
     Simulation sim(loadConfig());

src/test/ShipyardTest.cpp

@@ -23,7 +23,7 @@ static const ShipDef* findAvailableSchematic(const GameConfig& cfg)
 {
     for (const ShipDef& def : cfg.ships.ships)
     {
-        if (def.availableFromStart && !def.schematic.materials.empty())
+        if (def.unlockAtStationLevel == -1 && !def.schematic.materials.empty())
         {
             return &def;
         }