widescreen: draw creatures across the whole view; HUD: copy the cursor per thread

- Creatures were culled beyond 1024+200 x 768+200 screen pixels (cmp 4C8h /
  3C8h in both object passes): invisible in the right part of a wide view,
  and the player too once the centre passed 1224. The bounds follow the
  render size now.
- Centre immediates written as negatives (-200h / -180h), missed before:
  the row renderer's static object origin (0x62babb) and aiming at the
  cursor (0x4fb620).
- HUD: moved windows no longer shift the shared mouse cursor object; the
  cursor accessor (0x6550f0) hands them a per-thread shifted copy and writes
  back what they changed. World input on other threads read the shifted
  position now and then, which made hold-to-move jerky.

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

docs/hud.md

@@ -18,7 +18,7 @@ shared base methods are inside the scope):
 | screen-space vertices (`XYZRHW`) | `IDirect3DDevice7::DrawPrimitive` / `DrawIndexedPrimitive` (vtable 25 / 26) | x + dx |
 | 3D items (belt, equipment) | ortho projection centred on the screen | none needed |
 | mouse events | `cEvent_mouseMove` x at +4 (previous) and +0xc; button down / up x at +8 | x - dx, restored afterwards |
-| mouse cursor object (`*0xcdbadc`) | x at +4, previous x at +0xc (polled for hover, item pick-up `0x6559a0`) | x - dx, restored unless the window thread stored a new position |
+| mouse cursor object (`*0xcdbadc`, accessor `0x6550f0`) | x at +4, previous x at +0xc (polled for hover, item pick-up `0x6559a0`) | the accessor returns a per-thread copy with x - dx; dwords the window changed are written back afterwards |
 | `GetMouseClientPos` (`0x66e500`) | polled position | x - dx |
 
 ## Calls outside a window's scope
@@ -42,3 +42,13 @@ shared base methods are inside the scope):
 mouse events carry positions; category 5 events with subtype 0x10 test a point
 at +0x48 in `cUI_Window2::vf10`, but commands such as "open ESC menu" (0x11)
 keep unrelated data there.
+
+## Why the cursor is copied, not shifted
+
+UI windows render on the render thread while world input (picking,
+hold-to-move, `0x611f10`) reads the same cursor object on another thread.
+Shifting the shared object for the duration of a window's scope let the world
+sample a position ~400 px off now and then (jerky hold-to-move). Every user of
+the cursor goes through the accessor `0x6550f0`, so inside a moved window it
+returns a thread-local copy instead (with its own CRITICAL_SECTION at +0x24;
+copying and writing back hold the real object's lock).