Options: tabs Allgemein / Beute / Tastenbelegung with key bindings

- Options window in three tabs; the auto-pickup settings move to Beute;
  sliders move with their page; black sides like the save game screen.
- Tastenbelegung: every binding settable (click, press key; Esc cancels,
  Backspace unbinds), "Alle zurücksetzen" as a game button, saved on OK.
- Potions bindable (default unbound), named by the game's potion texts; the
  game's own potion hotkeys are off; bar tooltips show the bound key.
- Map (M), overview map (Tab, held) and labels (Alt, held) bindable; the
  game's own M / Tab / Alt handling is switched off.
- Save game key calls the game's save window code instead of a posted key.
- Teleportationstrank: fixed text replacement from startup (also the
  Ausdauertrank items, potion kind 5 as well).

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

src/game/ui/tabs.h

@@ -57,6 +57,13 @@ inline uint8_t* TabControl(void* sheet) {
     return *reinterpret_cast<uint8_t**>(static_cast<uint8_t*>(sheet) + kTabSheetControl);
 }
 
+constexpr size_t kTabControlActive = 0x84;  // u16
+
+inline uint16_t ActiveTab(void* sheet) {
+    const uint8_t* control = TabControl(sheet);
+    return control ? *reinterpret_cast<const uint16_t*>(control + kTabControlActive) : 0;
+}
+
 // The tab entries of a cUI_TabControl.
 inline uint8_t* TabEntries(uint8_t* control) {
     return *reinterpret_cast<uint8_t**>(control + kTabControlTabs);