feat(api): ✨ add combat_balance field

Co-Authored-By: Lilith Autocommit <noreply@atlilith.com>

src/simulator/api-gdext/src/lib.rs

@@ -2865,6 +2865,10 @@ impl IRefCounted for GdGameState {
                 // for these is Wave 2 work — for now we just need to satisfy
                 // the struct literal so the workspace compiles.
                 ransom_queue: Default::default(),
+                // p2-55f: combat balance config (defaults match prior
+                // hardcoded constants); GameState init reads from
+                // combat_balance.json once data-loader wiring lands.
+                combat_balance: Default::default(),
                 pending_capture_events: Default::default(),
                 // p3-10b: per-lair siege pressure state. Populated by the
                 // bridge as players begin sieges; serialized for save