Implemented research cost, tweaked some values.

Scripts/Tests/TestRunner.cs

@@ -16,6 +16,7 @@ public partial class TestRunner : Node
         Run("Robot research effects change robot stats", TestRobotResearchEffects);
         Run("Research completion applies effects once", TestResearchCompletionAppliesEffectsOnce);
         Run("Research execution pays resources and finishes", TestResearchExecutionPaysResourcesAndFinishes);
+        Run("Research cannot start without resources", TestResearchCannotStartWithoutResources);
         Run("Inventory add failure keeps inventory unchanged", TestInventoryAddFailureKeepsInventoryUnchanged);
         Run("Resource extraction and save data roundtrip", TestResourceSaveRoundtrip);
         Run("Robot save data roundtrip keeps robot state", TestRobotSaveRoundtrip);
@@ -238,6 +239,29 @@ public partial class TestRunner : Node
         AssertEqual(0, GameData.inventory.items.Count, "failed add should not create stacks");
     }
 
+    private void TestResearchCannotStartWithoutResources()
+    {
+        ResearchData researchData = new ResearchData
+        {
+            Id = "missing_stones",
+            Inputs = new List<Ingredient>
+            {
+                new Ingredient { Item = "stone", Amount = 3 }
+            },
+            Research = "basics",
+            CraftTime = 1.0,
+            Texture = "",
+            Effects = new List<ResearchEffect>()
+        };
+
+        Research research = new Research(researchData);
+        ResearchResult result = research.Execute(1.0);
+
+        AssertFalse(research.CanStart(), "research should not be startable");
+        AssertEqual(ResearchResult.FAILED, result, "research should fail without resources");
+        AssertEqual(ResearchState.UNDEFINED, research.state, "research state should stay unchanged");
+    }
+
     private void TestSplitSaveFilesRoundtrip()
     {
         GameData.inventory.AddItem(new Item { data = GameData.availableItems["water"] }, 7);