StoryQuest

Quest prerequisites, branches and co-op.

- Quest conditions: required quests, all/any mode, hide until available, and branch locks.
- Conditions editor with search, cycle detection, missing references and mixed-scope warnings.
- The journal shows locked quests, requirements, branch state and shared quests.
- Shared co-op quests (scope = SHARED) use one world progress: any player can start the quest
  and complete its objectives; start/complete commands, messages and dialogue run for every
  online player.
- /storyquest reset-shared [quest] resets world-shared progress.
- JSON export/import: /storyquest export [name] and
  /storyquest import <name> [merge|replace] [confirm].
  Full quest definitions are exported; imports are validated, atomic and create automatic DAT
  backups (last 20 are kept).
- /storyquest force-start starts a quest while bypassing conditions for testing.
- Existing worlds load with defaults (SOLO, no requirements, no branch); no migration is needed.
- DAT remains internal storage; JSON is the exchange format.
In 1.3.0 - New UI