Update documentation after refactoring: AGENTS.md, GAME_BRIEFING.md, skills.md

- Updated AGENTS.md to include store/ directory and clarify store architecture
- Updated GAME_BRIEFING.md Code Architecture section with store/ and legacy store info
- Updated skills.md with skill state management information
- Includes other refactoring changes (store hooks, component updates, etc.)

src/components/game/tabs/EquipmentTab.tsx

@@ -119,11 +119,24 @@ export function EquipmentTab() {
   const [selectedSlot, setSelectedSlot] = useState<EquipmentSlot | null>(null);
   const [deleteConfirm, setDeleteConfirm] = useState<{ instanceId: string; name: string } | null>(null);
 
-  // Use modular store directly
+  // Use modular store directly - MUST be called before any conditional returns
   const equippedInstances = useCombatStore((s) => s.equippedInstances);
   const equipmentInstances = useCombatStore((s) => s.equipmentInstances);
   
-  // Guard against undefined during initialization
+  // Get unequipped items - hooks must be called before conditional returns
+  const equippedIds = useMemo(() =>
+    new Set(Object.values(equippedInstances || {}).filter(Boolean)),
+    [equippedInstances]
+  );
+
+  const unequippedItems = useMemo(() =>
+    Object.values(equipmentInstances || {}).filter(
+      (inst) => !equippedIds.has(inst.instanceId)
+    ),
+    [equipmentInstances, equippedIds]
+  );
+
+  // Guard against undefined during initialization - AFTER all hooks
   if (!equippedInstances || !equipmentInstances) {
     return (
       <div className="p-4 text-center text-[var(--text-muted)]">
@@ -132,19 +145,6 @@ export function EquipmentTab() {
     );
   }
 
-  // Get unequipped items
-  const equippedIds = useMemo(() =>
-    new Set(Object.values(equippedInstances).filter(Boolean)),
-    [equippedInstances]
-  );
-
-  const unequippedItems = useMemo(() =>
-    Object.values(equipmentInstances).filter(
-      (inst) => !equippedIds.has(inst.instanceId)
-    ),
-    [equipmentInstances, equippedIds]
-  );
-
   // Equip an item to a slot
   const handleEquip = (instanceId: string, slot: EquipmentSlot) => {
     const instance = equipmentInstances[instanceId];
@@ -227,8 +227,13 @@ export function EquipmentTab() {
     }
   };
 
-  // Get unified effects for equipment stats
-  const unifiedEffects = useCombatStore((s) => s.equipmentInstances) ? getUnifiedEffects({ equipmentInstances, equippedInstances }) : null;
+  // Get unified effects for equipment stats - move hook before conditional
+  const equipmentInstancesForEffects = useCombatStore((s) => s.equipmentInstances);
+  const equippedInstancesForEffects = useCombatStore((s) => s.equippedInstances);
+  
+  const unifiedEffects = equipmentInstancesForEffects && equippedInstancesForEffects 
+    ? getUnifiedEffects({ equipmentInstances, equippedInstances })
+    : null;
 
   return (
     <div className="space-y-4 max-w-full overflow-x-hidden">