fix login issue*

lib/odinsea/game/inventory.ex

@@ -155,6 +155,34 @@ defmodule Odinsea.Game.Inventory do
     inv.slot_limit - map_size(inv.items)
   end
 
+  @doc """
+  Checks if the inventory has space for a given item and quantity.
+  Returns true if there's space, false otherwise.
+  """
+  def has_space?(%__MODULE__{} = inv, item_id, quantity) do
+    # Check if we can stack with existing items of same type
+    existing = find_by_id(inv, item_id)
+    
+    if existing do
+      # Can stack - check if existing stack + quantity <= slot_max
+      # For simplicity, assume slot_max of 9999 for stackable items
+      slot_max = existing[:slot_max] || 9999
+      existing_qty = existing.quantity || 0
+      
+      if existing_qty + quantity <= slot_max do
+        true
+      else
+        # Need additional slots for overflow
+        overflow = existing_qty + quantity - slot_max
+        slots_needed = div(overflow, slot_max) + if rem(overflow, slot_max) > 0, do: 1, else: 0
+        free_slots(inv) >= slots_needed
+      end
+    else
+      # New item - need at least one free slot
+      not full?(inv)
+    end
+  end
+
   @doc """
   Gets the next available slot number.
   Returns -1 if the inventory is full.