feat: Round 51 narrative systems improvements

- SaveData: update QuestState.Status comment to include Paused state
- QuestManager: add inline comment on AcceptQuest duplicate-accept guard
- QuestManager: wrap reward.Apply() in try-catch so exceptions don't
  corrupt already-committed Completed state
- QuestManager.UnlockBranches: support new conditionFlagEntries (invert/
  NOT logic) with graceful fallback to legacy conditionFlags
- QuestGiver: cache IQuestManager field in OnEnable; subscribe to
  OnQuestStateChanged for automatic cache invalidation instead of manual
  _cacheDirty = true after each Interact; remove per-call SL.GetOrDefault
- QuestGiver: replace hardcoded Chinese prompt strings with
  LocalizationManager.Get(key, 'UI') + inline fallback via GetPrompt()
- QuestSO: add BranchFlagEntry struct (flagId + invert) for NOT-logic
  branch conditions; add conditionFlagEntries to QuestBranch with
  HideInInspector on legacy conditionFlags for backward compat
- QuestModule: add static TTL cache (5 s) for FindAll<QuestSO>() in
  PopulateDependencyGraph to avoid re-scanning disk on every foldout open
- NpcSOEditor: add 'jump to localization file' button that pings and
  selects the UI table JSON in the Project window

Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>

Assets/_Game/Scripts/Core/Save/SaveData.cs

@@ -141,7 +141,7 @@ namespace BaseGames.Core.Save
         /// OnLoad 按此字段显式选择解析路径，杜绝依赖 Count > 0 的隐式推断。
         /// </summary>
         public int         DataVersion       = 2;
-        public string      Status;         // "NotStarted"|"Active"|"Completed"|"Failed"
+        public string      Status;         // "Unavailable"|"Available"|"Active"|"Paused"|"Completed"|"Failed"
         public int         ObjectiveIndex;
         /// <summary>新格式（Round 24+，DataVersion=2）：objectiveId → progressCount，重排目标顺序后存档不会错位。</summary>
         public Dictionary<string, int> ObjectiveProgress = new();