target single-building transfers by hovering, not by footprint coincidence

src/ui/GameWorldView.cpp

@@ -632,12 +632,16 @@ void GameWorldView::placeBlueprintAtTile(QPoint center)
 BlueprintGhostResolved GameWorldView::resolveBlueprintGhostHere(const BlueprintBuilding& building,
                                                                QPoint center) const
 {
-    // The one-building test reads the blueprint as stored, before locked types are
-    // dropped, so the gesture behaves the same however much the player has unlocked
-    // (REQ-UI-BLUEPRINT-TRANSFER).
+    // A single-building blueprint hit-tests the cursor for its transfer target; a
+    // constellation does not (REQ-UI-BLUEPRINT-TRANSFER). `center` is the cursor tile.
+    // The size is read from the blueprint as stored, before locked types are dropped, so
+    // the gesture behaves the same however much the player has unlocked.
+    const std::optional<QPoint> hoverTile =
+        m_buildMode.getBlueprint().buildings.size() == 1 ? std::make_optional(center)
+                                                         : std::nullopt;
     return resolveBlueprintGhost(m_sim->getFactoryState(), m_sim->getConfig(),
                                  building.type, center + building.offset, building.rotation,
-                                 m_buildMode.getBlueprint().buildings.size() == 1);
+                                 hoverTile);
 }
 
 std::string GameWorldView::unlockedRecipeId(const BlueprintBuilding& building) const