Restore aura visuals after loading a save

Saving marks effect objects dead, so after a load the Heldenmut /
Klingenblick buff was active but its aura effect (cObjectFX 842) was
gone. A few ticks after a save game has loaded, the effect is created
again for each such buff of a player hero (CreateAt + cEventFX 0x42,
as the art's cast effect does), with the buff's remaining time.

Shared game events (game/engine/events): engine tick and "save game
loaded" callbacks; the WASD mod uses the tick through it.

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

docs/todo.md

@@ -1,18 +1,12 @@
 # To do
 
-## Bug: skill "aura" effects are not drawn
+## Fixed: aura visuals missing after loading (2026-10-15)
 
-Reported 2026-10-14: the aura effects of some skills are missing. Not
-investigated yet. Things to check first:
-
-- whether vanilla (`[widescreen] Enabled=0`) draws them, i.e. whether the
-  widescreen or HUD patches cause it;
-- whether they are missing everywhere or only away from the screen centre;
-  if the latter, a clip test still using 1024x768 bounds, like the creature
-  clip (`0x4c8`/`0x3c8`) was;
-- effect objects (`cObjectFX`) in the object passes (`cWorldView0::DrawObjects`
-  `0x62e580` / `DrawObjects2` `0x6300d0`) and the light/effect list
-  (`+0xce14`, `0x41b1xx`).
+Saving marks effect objects (cObjectFX) dead; loading keeps the buff but drops
+the aura effect (type 842) that follows the hero. `src/mods/aura_restore.cpp`
+recreates it after a load for Heldenmut (0x3f7) and Klingenblick (0x3f8). Spell
+auras (Steinhaut, Lichtschild, ...) use other effects and are not covered
+yet; check them if their visuals go missing too.
 
 ## Better pathfinder (mouse clicks and monsters)