Quest book as one list: story, then side quests by region with ??? rows

The game's list builder runs on a reordered copy of the book: the story, then
one section per region (id blocks of 100 grouped by the region their quests
lie in, named as the megamap names regions), unknown quests as "???", the
rest joined to the nearest area, undiscovered counts. Act tabs hidden, page
turning kept. "Erledigte anzeigen" row toggles completed quests
([questbook] ShowCompleted).

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

CMakeLists.txt

@@ -75,6 +75,7 @@ add_library(sacredK SHARED
     src/mods/characters.cpp
     src/mods/mainmenu.cpp
     src/mods/mapreveal.cpp
+    src/mods/questbook.cpp
     src/mods/questfail.cpp
     src/mods/anticheat.cpp
     src/mods/loadingscreen.cpp