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/teleportpotion.h

@@ -0,0 +1,12 @@
+#pragma once
+
+#include <cstdint>
+
+namespace mods::teleportpotion {
+
+// cCreature::UseItem (mods/itemstack.cpp) asks first: true if `id` is a
+// Teleportationstrank used by the player hero; it then opened the portal
+// window instead of the drink.
+bool UseItem(void* creature, uint32_t id);
+
+} // namespace mods::teleportpotion