feat: Add Enhanced Input Manager for context management and key rebinding

- Implemented USS_EnhancedInputManager to manage input contexts with priority.
- Added methods for pushing, popping, and querying input contexts.
- Integrated input mode switching and key rebinding functionality.

feat: Introduce Inventory System Component for item management

- Created UBPC_InventorySystem to handle inventory operations such as adding, removing, and sorting items.
- Implemented weight management and slot organization features.
- Added event dispatchers for inventory changes.

feat: Develop Item Data Asset for item definitions

- Established UDA_ItemData as a base class for all items, encapsulating properties like type, weight, and stack limits.
- Included conditional sub-data structures for equipment, consumables, and inspect data.

feat: Create State Manager Component for player state management

- Developed UBPC_StateManager to manage player action states and overlays.
- Implemented gating logic for action requests and vital sign tracking.

feat: Implement Save Manager for game state persistence

- Introduced USS_SaveManager for handling save/load operations and slot management.
- Utilized FArchive for efficient binary serialization.

feat: Implement Damage Reception System for combat mechanics

- Created UBPC_DamageReceptionSystem to process incoming damage and apply resistance calculations.
- Added event dispatchers for damage reception and hit reactions.

Source/Framework/Private/Inventory/DA_ItemData.cpp

@@ -0,0 +1,121 @@
+// Copyright Epic Games, Inc. All Rights Reserved.
+// UE5 Modular Game Framework — DA_ItemData Implementation
+
+#include "Inventory/DA_ItemData.h"
+#include "GameplayTagsManager.h"
+
+DEFINE_LOG_CATEGORY_STATIC(LogItemData, Log, All);
+
+UDA_ItemData::UDA_ItemData()
+{
+	ItemType = EItemType::Misc;
+	StackLimit = 1;
+	Weight = 0.0f;
+	bCanBeDropped = true;
+	bIsKeyItem = false;
+	bHasInspectMode = false;
+}
+
+// ============================================================================
+// Overrides
+// ============================================================================
+
+void UDA_ItemData::PostLoad()
+{
+	Super::PostLoad();
+
+	// Key items cannot be dropped — enforce.
+	if (bIsKeyItem && bCanBeDropped)
+	{
+		UE_LOG(LogItemData, Warning, TEXT("DA_ItemData::PostLoad — '%s': bIsKeyItem && bCanBeDropped — forcing bCanBeDropped = false"),
+			*ItemTag.GetTagName().ToString());
+		bCanBeDropped = false;
+	}
+
+	// Validate tag registration.
+	if (ItemTag.IsValid())
+	{
+		UGameplayTagsManager& TagManager = UGameplayTagsManager::Get();
+		FGameplayTag CheckTag;
+		if (!TagManager.RequestGameplayTag(ItemTag.GetTagName(), CheckTag))
+		{
+			UE_LOG(LogItemData, Warning, TEXT("DA_ItemData::PostLoad — '%s': ItemTag '%s' is not registered in the tag table!"),
+				*GetName(), *ItemTag.GetTagName().ToString());
+		}
+	}
+}
+
+#if WITH_EDITOR
+void UDA_ItemData::PostEditChangeProperty(FPropertyChangedEvent& PropertyChangedEvent)
+{
+	Super::PostEditChangeProperty(PropertyChangedEvent);
+
+	FName PropertyName = PropertyChangedEvent.GetPropertyName();
+
+	// Auto-enforce key item rule.
+	if (PropertyName == GET_MEMBER_NAME_CHECKED(UDA_ItemData, bIsKeyItem) && bIsKeyItem)
+	{
+		bCanBeDropped = false;
+	}
+}
+
+bool UDA_ItemData::ValidateItemData(FString& OutErrors) const
+{
+	TArray<FString> Errors;
+
+	// Check required fields.
+	if (!ItemTag.IsValid())
+	{
+		Errors.Add(TEXT("ItemTag is invalid/empty."));
+	}
+
+	if (DisplayName.IsEmpty())
+	{
+		Errors.Add(TEXT("DisplayName is empty."));
+	}
+
+	if (Description.IsEmpty())
+	{
+		Errors.Add(TEXT("Description is empty."));
+	}
+
+	// Check key item cannot be dropped.
+	if (bIsKeyItem && bCanBeDropped)
+	{
+		Errors.Add(TEXT("bIsKeyItem is true but bCanBeDropped is also true. Key items cannot be dropped."));
+	}
+
+	// Check consumable has valid data.
+	if (ItemType == EItemType::Consumable &&
+		ConsumableData.HealthRestore <= 0.0f && ConsumableData.StressReduce <= 0.0f)
+	{
+		Errors.Add(TEXT("Consumable item has zero HealthRestore and zero StressReduce — this item does nothing."));
+	}
+
+	// Check weapon has damage.
+	if (ItemType == EItemType::Weapon && EquipmentData.Damage <= 0.0f)
+	{
+		Errors.Add(TEXT("Weapon item has zero Damage."));
+	}
+
+	// Check stack limits.
+	if (StackLimit < 1)
+	{
+		Errors.Add(TEXT("StackLimit must be >= 1."));
+	}
+
+	// Build output string.
+	for (const FString& Err : Errors)
+	{
+		OutErrors += TEXT("- ") + Err + TEXT("\n");
+	}
+
+	if (Errors.Num() > 0)
+	{
+		UE_LOG(LogItemData, Warning, TEXT("DA_ItemData::ValidateItemData — '%s' has %d errors:\n%s"),
+			*ItemTag.GetTagName().ToString(), Errors.Num(), *OutErrors);
+	}
+
+	return Errors.Num() == 0;
+}
+#endif