A failed quest gets its flags cleared and its quest book entries removed
after its failure script ran, so the quest giver can offer it again; quests
failed before the mod are reset once after loading. Quest table and quest
book in game/engine/quests.h, measurements in docs/quests.md.
Co-Authored-By: Claude Opus 5.5 (1M context) <noreply@anthropic.com>
