Teleportationstrank: yellow potions open the portal window

- Every yellow potion (potion kind 5, all stages) is a Teleportationstrank:
  drinking it posts the teleporter's event to the busy dialog with the
  hero's known portals; the potion is used up only when the hero teleports
  from that window (closing it keeps the potion)
- Names replaced in every game text (ReplaceInTexts), so item names and the
  bottom bar's quick-select tooltip read Teleportationstrank; GameText reads
  the game's own text
- HeroIndex / HeroInventory moved to skillslots for shared use
- docs/teleport-potion.md; walking animation after loading noted in todo

Co-Authored-By: Claude Opus 5.5 (1M context) <noreply@anthropic.com>

src/mods/itemstack.cpp

@@ -31,6 +31,7 @@
 //   (0x5dc3f0; cell rects from CellRect 0x5dd530).
 
 #include "mods/itemstack.h"
+#include "mods/teleportpotion.h"
 
 #include <windows.h>
 
@@ -308,11 +309,16 @@ uint32_t __fastcall ObjMgr_DestroyObject(void* self, void* edx, uint32_t id, uin
     return ObjMgr_DestroyObject_original(self, edx, id, a, b, c);
 }
 
-// cCreature::UseItem (0x54a8f0, ret 4): a new drink starts.
+
+// cCreature::UseItem (0x54a8f0, ret 4): a new drink starts (a
+// Teleportationstrank opens the portal window instead, teleportpotion.cpp).
 char __fastcall Creature_UseItem(void* self, void* edx, uint32_t id);
 RE_HOOK(0x0054a8f0, Creature_UseItem);
 char __fastcall Creature_UseItem(void* self, void* edx, uint32_t id) {
     g_drunk = 0;
+    if (mods::teleportpotion::UseItem(self, id)) {
+        return 0;
+    }
     return Creature_UseItem_original(self, edx, id);
 }