Implement config-driven unlock groups so that multiple things can be unlocked at once (including buildings)

src/lib/core/SchematicChoiceOption.h

@@ -3,23 +3,43 @@
 #include <string>
 #include <vector>
 
+// The kind of a single granted schematic within an unlock option.
 enum class SchematicType
 {
     Ship,
     Module,
-    Recipe,
-    Artifact
+    Building,
+    Recipe
+};
+
+// One item granted by an unlock group (REQ-LOCK-EXPLICIT), shown in the
+// schematic choice dialog's granted-items list.
+struct GrantedSchematic
+{
+    SchematicType type;
+    std::string id;
+    std::string displayName;
 };
 
 // One option presented to the player in the schematic choice dialog
 // (REQ-DEF-SCHEMATIC-DROP). Built by the simulation when enemy stations are
-// destroyed; the UI reads these to populate the dialog.
+// destroyed; the UI reads these to populate the dialog. A non-artifact option
+// represents one unlock group; selecting it awards the whole group.
 struct SchematicChoiceOption
 {
-    std::string schematicId;
-    SchematicType type;
+    bool isArtifact = false;
+
+    // Unlock group id (empty for the artifact option).
+    std::string unlockGroupId;
+
+    // Display name shown as the option's title: the unlock group's derived name,
+    // or "Artifact" for the artifact option.
     std::string displayName;
 
+    // The ships, modules, buildings, and assembler recipes this group grants
+    // (empty for the artifact option).
+    std::vector<GrantedSchematic> grantedItems;
+
     // Ids of miner/assembler recipes that would newly become implicitly
     // unlocked (REQ-LOCK-IMPLICIT) if this option is selected. Sorted
     // alphabetically by display name; empty if none.