refactor: Round 53 remove all legacy backward-compatibility code

- QuestSO: remove giverNpcId, prerequisiteQuests/Flags/FlagsLogic, failCondition,
  conditionFlags, npcDialogueKey fields; simplify GiverNpcId property to giverNpc?.npcId;
  clean ValidatePrerequisiteCycles/HasPrerequisiteCycle to use prerequisites.questDependencies;
  remove ValidateBranchDialogueKeys migration warning block; clean QuestPrerequisite doc
- QuestManager: remove OnLoad DataVersion 1/2 migration paths (ProgressCounts, hasNewFormat/
  useNewFormat); remove CheckQuestDepsAndFlags old-field fallback (prerequisiteQuests/Flags);
  remove UnlockBranches conditionFlags fallback; remove DispatchEvent failCondition fallback;
  fix ValidatePrerequisites DFS to scan prerequisites.questDependencies
- SaveData: remove ProgressCounts (Obsolete), ObjectiveIndex (unused), GiverNpcId (never
  written) fields from QuestState; simplify DataVersion doc comment
- QuestSOEditor: replace migration-only editor with minimal DrawDefaultInspector
- QuestModule: update all prerequisiteQuests/conditionFlags/npcDialogueKey/failCondition
  references to canonical new fields; update ValidateBranchFlags check 10
- FlagAuditModule: replace conditionFlags/prerequisiteFlags scans with conditionFlagEntries/
  prerequisites.flagCondition.flags
- NpcSO: remove QuestSO.giverNpcId reference from npcId tooltip
- NpcAffinityEvent/RewardSO: update doc comments to reference giverNpc instead of giverNpcId

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

Assets/_Game/Scripts/Editor/Modules/FlagAuditModule.cs

@@ -155,17 +155,17 @@ namespace BaseGames.Editor.Modules
             // 3. 扫描 QuestSO
             foreach (var quest in AssetOperations.FindAll<QuestSO>())
             {
-                // branches[i].conditionFlags → 读取
+                // branches[i].conditionFlagEntries → 读取
                 if (quest.branches != null)
                     foreach (var branch in quest.branches)
-                        if (branch.conditionFlags != null)
-                            foreach (var fid in branch.conditionFlags)
-                                if (!string.IsNullOrEmpty(fid))
-                                    GetOrCreate(fid).readLocations.Add(($"任务分支条件 [{quest.name}]", quest));
+                        if (branch.conditionFlagEntries != null)
+                            foreach (var entry in branch.conditionFlagEntries)
+                                if (!string.IsNullOrEmpty(entry.flagId))
+                                    GetOrCreate(entry.flagId).readLocations.Add(($"任务分支条件 [{quest.name}]", quest));
 
-                // prerequisiteFlags → 读取
-                if (quest.prerequisiteFlags != null)
-                    foreach (var fid in quest.prerequisiteFlags)
+                // prerequisites.flagCondition.flags → 读取
+                if (quest.prerequisites.flagCondition.flags != null)
+                    foreach (var fid in quest.prerequisites.flagCondition.flags)
                         if (!string.IsNullOrEmpty(fid))
                             GetOrCreate(fid).readLocations.Add(($"任务前置标志 [{quest.name}]", quest));
             }