player: add equipment slots and inventory overlay

- Weapon/armor equip slots persist until replaced
- Numbered inventory overlay with I key
- E to equip from inventory, U to use potions"

Signed-off-by: NotAShelf <raf@notashelf.dev>
Change-Id: I474acd676da3b768c1aac24f75f303e86a6a6964

src/items.h

@@ -8,7 +8,16 @@
 // Spawn items for a floor
 void item_spawn(Item items[], int *count, Map *map, int floor);
 
-// Use an item
+// Use an item (apply effect, only potions are consumed)
 void item_use(Player *p, Item *i);
 
+// Get item name for display
+const char *item_get_name(const Item *i);
+
+// Get item description
+const char *item_get_description(const Item *i);
+
+// Get item power value
+int item_get_power(const Item *i);
+
 #endif  // ITEMS_H