Map: zoomed-view symbols centred, 10x reveal and enemy range; progress screen on the menu background

- Megamap / TAB map zoomed view: heroes' markers and the other symbols
  (integer 200h centre immediates) follow the view's centre.
- Map reveal: the hero's reveal stamp scaled 10x (mods/mapreveal.cpp,
  docs/map-reveal.md); creatures on the zoomed map shown within 10x the
  sight range.
- Load / save progress screen drawn on the rock background across the full
  width, the picture blended over it (mods/loadingscreen.cpp); the classic
  1024x768 frame is gone.

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

docs/todo.md

@@ -234,15 +234,17 @@ repeatable ones (ids 2600..3599, cloned by Quest_End) and DQ_ dynamic quests;
 which of them count for an area, and how the book groups by area, is still to
 be measured.
 
-## Megamap zoomed view: markers shifted (2026-10-25)
+## Megamap: zoom not centred on the hero (2026-10-25)
 
-Reported: on the M map, clicking a location to zoom in shows the markers on
-the zoomed map wrong / shifted (megamap.cpp).
+Reported: the zoomed view does not start centred on the hero. The game zooms
+on the large map's zoom point +0xc0438 (the mouse position, updated while the
+mouse is outside the zoom buttons +0xc0538; 0x6ca47b) plus the scroll. Open:
+how the user zoomed (buttons / key / click); then zoom on the hero for
+buttons and keys.
 
-## Load / save progress screen: rock background (2026-10-25)
+## Inventory drawn without its dark backgrounds (2026-10-25, intermittent)
 
-Reported: the progress screen shown while loading / saving does not use the
-rock-wall background of the other menu screens yet (hud::RenderMenuFrame,
-docs/screens.md). The GDI progress screen is DxDriver7_LoadingScreen
-0x6469d0 (1024x768, game/addresses.h); pictures PAK\loading0/1.bmp,
-loadgame.bmp, savegame.bmp, LoadingUW00/01.bmp.
+Reported twice: on opening the inventory the item list had no dark
+background behind the grid, and the tab texts had an odd background colour.
+Looks like render state (texture / blend / colour) left behind by an earlier
+draw; not reproduced yet. To find out: what was open or shown just before.