Characters: reset a difficulty

"Zuruecksetzen" in the load window lists the selected character's worlds
and asks for confirmation. The world goes (a copy in characters\deleted),
with an autosave of it, and the shared hero's story completion of that
difficulty is cleared. The dialog is one generic list (title + entries).

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

docs/characters.md

@@ -222,6 +222,17 @@ keeping the gap before "Beenden".
   (`game::NewButtonLike`); their captions are our own text ids with
   overrides (texts.cpp checks overrides for our ids too).
 
+- "Zurücksetzen" (below Umbenennen; a selected character with the shared
+  hero and a world, not the one being played) lists the character's worlds,
+  then asks "<Welt> zurücksetzen?". A reset (decided 2026-10-20) removes the
+  world section (a copy goes to `charactersdeletedCharacterNN.sacredK.<section>.PAK`)
+  and an autosave of that world, and clears the shared hero's story
+  completion of that difficulty (hero header +0xed + d); the game counts it
+  per difficulty, so the next difficulty closes in both campaigns unless a
+  world keeps it open. The hero keeps everything else.
+- The dialog is one generic list: each kind fills a title and entries
+  (FillDialog), "Abbrechen" last.
+
 ### Load
 
 `cEngine::Load` (0x61b790) of a listed row: the chosen world and the hero are
@@ -275,7 +286,6 @@ kept, the newest file overall is the shared hero.
 
 ## Open
 
-- Reset a difficulty.
 - Silent autosave every 10 minutes.
 - Quickload (row 0) does not know characters.
 - Multiplayer (see `todo.md`).