Characters: 16:9 "Spielen" screen, autosave interval option

- Shared screen kit (mods/screen, docs/screens.md): a 1365x768 canvas
  centred in the render width on our own dark background, the game's
  frames and buttons; the main menu renders full width while it is shown.
- The load window (cUI_Savegame) is replaced by the Spielen screen:
  character list, hero panel, campaign x difficulty grid, save/autosave
  choice, rename/delete/reset/new character dialogs.
- Migrated characters without a shared hero load their hero's world
  first, then start the new world.
- Options, Allgemein: autosave interval (Aus/5/10/15/30 minutes).

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

docs/todo.md

@@ -184,12 +184,10 @@ From the characters rework (`docs/characters.md`, request of 2026-10-19):
   are one byte per difficulty in cStatsManager +0x5704 (read 0x424be0) and
   travel in the save header (+0x88..+0x98) and the hero file. Done
   2026-10-20 (docs/characters.md).
-- **Autosave interval in the options window** (now only
-  `sacredK.ini` `[characters] AutosaveMinutes`).
-- **Quickload (row 0) does not know characters.** Ctrl+Z saves into the
-  current character, but the quickload event (0x116, engine +0x68 = row,
-  flag 0x200) loads `GAME00.PAK`, which is not listed; make it reload the
-  current character's world (or its newer autosave).
+- **Autosave interval in the options window.** Done 2026-10-20: Allgemein
+  page, "Spielstände" frame (docs/options.md).
+- Quickload (row 0, `GAME00.PAK`) does not know characters; not needed
+  (user, 2026-10-20).
 
 ## Two saves in a row (2026-10-20, not reproduced)
 
@@ -200,10 +198,20 @@ flag 0x40 is set in cEngine::ReceiveEvent at 0x618876 (quicksave),
 log of the event that sets the flag (dwords 0..9) did not catch it again;
 add it back if it shows.
 
+Once (2026-10-20, not reproduced) an autosave seemed to fire right after a
+new world started through the hero chain (Character08: hero world loaded,
+then the new world). The log of that run had no save at all; the timed
+autosave counts from the game start (OnGameStart).
+
 ## Savegames screen redesign ("Spielen")
 
 Asked 2026-10-20: redesign the load window (cUI_Savegame, the "Spielen"
 screen, characters.cpp): show a render of the selected character, use the
-space far better. The user looks for 16:9 artwork so the screens can be
-widened beyond the 1024 frame (now drawn in a centred 1024x768 viewport with
-black sides, hud.cpp FrameScope).
+space far better. No 16:9 artwork exists for the game (user, 2026-10-20):
+we design our own UIs, using the width beyond the 1024 frame (now drawn in
+a centred 1024x768 viewport with black sides, hud.cpp FrameScope). Design
+for 16:9 (1920x1080, 1365x768 UI units), not ultrawide (user). Screen done
+2026-10-20 (docs/characters.md, "Spielen screen"; docs/screens.md). Open:
+the render of the selected hero (the hero panel shows text only; reuse
+cUI_Character's 3D hero?), list scrolling beyond 9 characters, larger
+heading font.