drop CombatSystem's unused BuildingSystem parameter

The parameter was already commented out in the definition — combat resolution
never touched it. Removing it also removes the last reference to BuildingSystem
from CombatSystem, so the forward declaration goes too.

Co-Authored-By: Claude <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01YHcUerKAZKWNvSKJxYKbnG

src/balancing/ArenaSimulation.cpp

@@ -329,7 +329,7 @@ void ArenaSimulation::tick()
     m_repairSystem->tick(m_currentTick, beamFiredEvents);
 
     // Combat resolution (tick step 8).
-    m_combatSystem->tick(m_currentTick, m_admin, *m_buildingSystem, beamFiredEvents);
+    m_combatSystem->tick(m_currentTick, m_admin, beamFiredEvents);
     m_beamFiredEvents.insert(m_beamFiredEvents.end(), beamFiredEvents.begin(), beamFiredEvents.end());
     m_combatSystem->applyPendingDamage(m_currentTick, m_admin);
 

src/lib/ecs/system/CombatSystem.cpp

@@ -17,7 +17,6 @@ CombatSystem::CombatSystem(const GameConfig& config)
 
 void CombatSystem::tick(Tick currentTick,
                          EntityAdmin& admin,
-                         BuildingSystem& /*buildings*/,
                          std::vector<BeamFiredEvent>& outBeamFiredEvents)
 {
 	TRACE();

src/lib/ecs/system/CombatSystem.h

@@ -15,7 +15,6 @@
 
 #include "entt/entity/entity.hpp"
 
-class BuildingSystem;
 class EntityAdmin;
 
 class CombatSystem
@@ -25,7 +24,6 @@ public:
 
     void tick(Tick currentTick,
               EntityAdmin& admin,
-              BuildingSystem& buildings,
               std::vector<BeamFiredEvent>& outBeamFiredEvents);
 
     void applyPendingDamage(Tick currentTick, EntityAdmin& admin);

src/lib/sim/Simulation.cpp

@@ -267,8 +267,7 @@ void Simulation::tick()
     m_repairSystem->tick(m_currentTick, m_beamFiredEvents);
 
     // Step 8: combat resolution
-    m_combatSystem->tick(m_currentTick, m_admin,
-                         *m_buildingSystem, m_beamFiredEvents);
+    m_combatSystem->tick(m_currentTick, m_admin, m_beamFiredEvents);
 
     // Step 8b: deferred damage whose impact tick has arrived
     m_combatSystem->applyPendingDamage(m_currentTick, m_admin);

src/test/CombatSystemTest.cpp

@@ -112,7 +112,7 @@ TEST_CASE("CombatSystem: ship fires when cooldown=0 and target in range", "[comb
     const float hpBefore = f.admin.get<HealthComponent>(player).hp;
 
     std::vector<BeamFiredEvent> events;
-    f.combat.tick(0, f.admin, f.buildings, events);
+    f.combat.tick(0, f.admin, events);
     f.combat.applyPendingDamage(5, f.admin);
 
     REQUIRE(f.admin.get<HealthComponent>(player).hp < hpBefore);
@@ -145,13 +145,13 @@ TEST_CASE("CombatSystem: cooldown prevents firing before it expires", "[combat]"
     };
 
     std::vector<BeamFiredEvent> events;
-    f.combat.tick(0, f.admin, f.buildings, events);
+    f.combat.tick(0, f.admin, events);
     REQUIRE_FALSE(enemyFiredIn(events));
 
-    f.combat.tick(1, f.admin, f.buildings, events);
+    f.combat.tick(1, f.admin, events);
     REQUIRE_FALSE(enemyFiredIn(events));
 
-    f.combat.tick(2, f.admin, f.buildings, events);
+    f.combat.tick(2, f.admin, events);
     REQUIRE(enemyFiredIn(events));
 }
 
@@ -166,7 +166,7 @@ TEST_CASE("CombatSystem: no fire when target is out of range", "[combat]")
     f.wireEnemyTarget(enemy, player);
 
     std::vector<BeamFiredEvent> events;
-    f.combat.tick(0, f.admin, f.buildings, events);
+    f.combat.tick(0, f.admin, events);
     REQUIRE(events.empty());
 }
 
@@ -309,7 +309,7 @@ TEST_CASE("CombatSystem: damage not applied before impact tick", "[combat]")
     const float hpBefore = f.admin.get<HealthComponent>(player).hp;
 
     std::vector<BeamFiredEvent> events;
-    f.combat.tick(0, f.admin, f.buildings, events);
+    f.combat.tick(0, f.admin, events);
 
     for (Tick t = 1; t < 5; ++t)
     {
@@ -331,7 +331,7 @@ TEST_CASE("CombatSystem: damage applied exactly at impact tick", "[combat]")
     const float hpBefore = f.admin.get<HealthComponent>(player).hp;
 
     std::vector<BeamFiredEvent> events;
-    f.combat.tick(0, f.admin, f.buildings, events);
+    f.combat.tick(0, f.admin, events);
     f.combat.applyPendingDamage(5, f.admin);
 
     REQUIRE(f.admin.get<HealthComponent>(player).hp < hpBefore);
@@ -348,7 +348,7 @@ TEST_CASE("CombatSystem: damage silently dropped if target already dead", "[comb
     f.wireEnemyTarget(enemy, player);
 
     std::vector<BeamFiredEvent> events;
-    f.combat.tick(0, f.admin, f.buildings, events);
+    f.combat.tick(0, f.admin, events);
 
     f.ships.despawn(player);
 
@@ -371,7 +371,7 @@ TEST_CASE("CombatSystem: damage still applied if shooter already dead", "[combat
     const float hpBefore = f.admin.get<HealthComponent>(player).hp;
 
     std::vector<BeamFiredEvent> events;
-    f.combat.tick(0, f.admin, f.buildings, events);
+    f.combat.tick(0, f.admin, events);
 
     f.ships.despawn(enemy);