Export screen: widescreen frame, black sides, slots can be cleared

- cUI_Character (export) and cUI_Savegame draw inside the centred 1024x768
  frame (viewport) with the render target beside it cleared black; the
  export screen's 3D heroes were stretched across the wide viewport, away
  from their labels and hit areas.
- Export screen shows the game's erase button for an occupied slot and
  reloads the heroes after a delete. Overwriting was already the game's
  own path once clicks hit the right slot.
- game/ui/control.h: shared show/hide for cUI_Control2.

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

tools/names.txt

@@ -301,3 +301,11 @@
 0x006e6ae0 cUI_Tooltip::SetText              # (textId, text*, fixedWidth), ret 0xc
 0x006e7730 cUI_Tooltip::Layout               # measures the text, width = longest line + 8 unless flag 0x100
 0x0075ac70 cUI_Manager::ShowTooltip          # (x, y, text, ?, flags, show)
+
+# Character selection / export screen (src/mods/charexport.cpp)
+0x0070c760 cUI_Character::SetMode          # (mode), ret 4: +0x390 (4 selection, 5 export, 6 overwrite confirm)
+0x0070c440 cUI_Character::SelectSlot       # (char slot, -1 none), ret 4
+0x0070d0f0 cUI_Character::ExecuteAction    # (action, slot, extra), ret 0xc: 6 export into slot, 9 export (confirm if occupied)
+0x0070e650 cUI_Character::OnConfirmButton  # the right-hand button (Exportieren, ...)
+0x007f01a0 HeroSlots_DeleteHero           # (slot + 1), thiscall on 0x7d7c40(), ret 4: deletes Save\Hero%02d.pax
+0x00731e70 cUI_Control2::SetFlags          # (flags), ret 4: bit 0 = visible (show)