Add inventory persistence restore hook

Docs/InventoryDataModel.md

@@ -100,7 +100,9 @@ player's inventory without a translation layer.
 Save/load responsibilities:
 
 - Save the player inventory from `UAgrarianInventoryComponent::Items`.
-- Restore the stack array onto the component during load.
+- Restore the stack array through
+  `UAgrarianInventoryComponent::RestoreSavedItems` during load so HUD/UI
+  listeners receive `OnInventoryChanged`.
 - Recompute derived values such as total weight after load from stack data.
 - Avoid saving UI-only selection state as part of the inventory model.
 

Docs/TechnicalDesignDocument.md

@@ -144,6 +144,12 @@ array, shows occupied slots, total carried weight, and a short visible stack
 list, and leaves mutation actions on the existing server-authoritative commands
 and RPCs until a full UMG inventory screen is introduced.
 
+Inventory persistence saves `UAgrarianInventoryComponent::Items` into
+`FAgrarianSavedPlayer::Inventory` and restores through
+`UAgrarianInventoryComponent::RestoreSavedItems`. Restore broadcasts
+`OnInventoryChanged`, which keeps the MVP HUD panel and future UI listeners in
+sync after load while preserving total weight as a derived value.
+
 ## Time And Environment
 
 The MVP gameplay calendar target is: