一刀砍干净 HistoryManager 所有 O(N) stat 全扫路径

继上次只修 hot path 之后, 把残留的所有冷热路径都改成 raw json
直接操作, 彻底消灭 load_history_index 内的 stat 循环.

修改:
1. _migrate_paths_once: 启动时一次性路径归一化, 抽样 5 条 60% 阈值
   决定是否需要全量迁移, 之后所有路径都是当前 base_path 下的有效绝对路径
2. load_history_index: 简化为 raw read + from_dict + sort, 0 stat
   N=513 时只需几 ms (旧版 ~60ms)
3. delete_history_item: 改 raw json filter
4. _cleanup_old_records: 改 raw json sort + slice
5. 删除已无调用方的 _save_history_index / _fix_history_path

至此 hot path (生成完成, 点击历史项) 与 cold path (删除, 启动清理)
都不再触发 N 次 stat. 唯一保留全量读的 load_history_index 也只有
refresh_history 一处真实调用方.

@@ -812,6 +812,13 @@ class HistoryManager:
 
         self.logger.debug(f"历史记录管理器初始化完成，存储路径: {self.base_path}")
 
+        # 启动时一次性把过期绝对路径归一化到当前 base_path,
+        # 之后 load_history_index 不再做任何 stat 循环
+        try:
+            self._migrate_paths_once()
+        except Exception as e:
+            self.logger.warning(f"启动路径迁移失败 (可忽略): {e}")
+
     def save_generation(self, image_bytes: bytes, prompt: str, reference_images: List[bytes],
                         aspect_ratio: str, image_size: str, model: str) -> str:
         """保存生成的图片到历史记录
@@ -929,80 +936,106 @@ class HistoryManager:
                 pass
             return None
 
-    def _fix_history_path(self, stored_path: Path, timestamp: str) -> Path:
-        """修正历史记录中的路径，使其指向当前 base_path
+    def _migrate_paths_once(self):
+        """启动时一次性路径归一化（取代过去每次 load 都修正的循环）。
+
+        历史背景：旧版本 index.json 存绝对路径。.app 重打包或存储位置变更
+        后，老路径失效。过去做法是 load_history_index 每次都全扫 stat 修正，
+        N=513 时主线程阻塞 ~60ms × N 次/会话，Mac 上累计触发 jetsam SIGKILL。
 
-        存储迁移后，index 里的绝对路径可能指向旧位置（如 .app 内部），
-        而实际文件已在新的 base_path 下。用 timestamp + 文件名重建路径。
+        现在改成只在启动时跑一次：
+        1. 抽样前 5 条，60% 以上路径有效 → 跳过（绝大多数启动走这条 fast path）
+        2. 否则全量重写所有路径并 save，之后 load_history_index 直接信任 raw
         """
-        if stored_path.exists():
-            return stored_path
+        if not self.history_index_file.exists():
+            return
+        try:
+            with open(self.history_index_file, 'r', encoding='utf-8') as f:
+                raw = json.load(f)
+        except Exception as e:
+            self.logger.warning(f"_migrate_paths_once 读取 index 失败: {e}")
+            return
+        if not isinstance(raw, list) or not raw:
+            return
+
+        sample = [d for d in raw[:5] if isinstance(d, dict)]
+        if not sample:
+            return
+        ok = 0
+        for d in sample:
+            p = d.get('generated_image_path')
+            if p and Path(p).exists():
+                ok += 1
+        # 60% 阈值：少数损坏可能是孤立文件被人手动删，不需要全迁移
+        if ok * 10 >= len(sample) * 6:
+            self.logger.info(
+                f"[migrate_paths] 抽样 {ok}/{len(sample)} 路径有效，跳过迁移"
+            )
+            return
 
-        # 尝试在当前 base_path 下找到对应文件
-        corrected = self.base_path / timestamp / stored_path.name
-        if corrected.exists():
-            return corrected
+        self.logger.info(
+            f"[migrate_paths] 抽样 {ok}/{len(sample)} 路径有效，开始全量迁移 {len(raw)} 条"
+        )
+        changed = 0
+        for d in raw:
+            if not isinstance(d, dict):
+                continue
+            ts = d.get('timestamp')
+            if not ts:
+                continue
+            gen_p = d.get('generated_image_path')
+            if gen_p and not Path(gen_p).exists():
+                cand = self.base_path / ts / Path(gen_p).name
+                if cand.exists():
+                    d['generated_image_path'] = str(cand)
+                    changed += 1
+            refs = d.get('reference_image_paths') or []
+            new_refs = []
+            for r in refs:
+                if Path(r).exists():
+                    new_refs.append(r)
+                else:
+                    cand = self.base_path / ts / Path(r).name
+                    if cand.exists():
+                        new_refs.append(str(cand))
+                        changed += 1
+                    else:
+                        new_refs.append(r)
+            d['reference_image_paths'] = new_refs
 
-        return stored_path
+        if changed > 0:
+            self.logger.info(f"[migrate_paths] 修正 {changed} 个路径, 写回 index.json")
+            try:
+                with open(self.history_index_file, 'w', encoding='utf-8') as f:
+                    json.dump(raw, f, ensure_ascii=False, indent=2)
+            except Exception as e:
+                self.logger.error(f"[migrate_paths] 写回失败: {e}")
 
     def load_history_index(self) -> List[HistoryItem]:
-        """加载历史记录索引
+        """加载历史记录索引（仅 raw read + from_dict + sort）。
 
-        Returns:
-            历史记录项列表，按时间戳倒序排列
+        路径修正已下放到 __init__ 时的 _migrate_paths_once，
+        load 路径完全没有 stat 系统调用，N=513 时只需几 ms。
         """
         if not self.history_index_file.exists():
             return []
-
         try:
-            self.logger.info("[load_history_index] 开始读取 index.json")
-            _flush_logs()
             with open(self.history_index_file, 'r', encoding='utf-8') as f:
                 data = json.load(f)
-            self.logger.info(f"[load_history_index] JSON 解析完成, {len(data)} 条原始数据")
-            _flush_logs()
-
-            history_items = [HistoryItem.from_dict(item) for item in data]
-            total = len(history_items)
-
-            # 修正可能过期的绝对路径（存储迁移后旧路径不再有效）
-            # 每条 item 对每个 path 都要 stat; 这是 UI 主线程上可能拖死的点
-            needs_save = False
-            for idx, item in enumerate(history_items):
-                fixed_gen = self._fix_history_path(item.generated_image_path, item.timestamp)
-                if fixed_gen != item.generated_image_path:
-                    item.generated_image_path = fixed_gen
-                    needs_save = True
-
-                fixed_refs = []
-                for ref_path in item.reference_image_paths:
-                    fixed_ref = self._fix_history_path(ref_path, item.timestamp)
-                    if fixed_ref != ref_path:
-                        needs_save = True
-                    fixed_refs.append(fixed_ref)
-                item.reference_image_paths = fixed_refs
-
-                if (idx + 1) % 20 == 0:
-                    self.logger.info(f"[load_history_index] 路径修正进度 {idx + 1}/{total}")
-                    _flush_logs()
-
-            self.logger.info(f"[load_history_index] 路径修正完成, needs_save={needs_save}")
-            _flush_logs()
-
-            # 路径修正后持久化，避免每次都修正
-            if needs_save:
-                self.logger.info("检测到历史记录路径变更，已自动修正")
-                self._save_history_index(history_items)
-                _flush_logs()
-
-            # 按时间戳倒序排列
-            history_items.sort(key=lambda x: x.timestamp, reverse=True)
-            self.logger.info(f"[load_history_index] 返回 {total} 条")
-            _flush_logs()
-            return history_items
+            if not isinstance(data, list):
+                return []
+            items: List[HistoryItem] = []
+            for d in data:
+                if not isinstance(d, dict):
+                    continue
+                try:
+                    items.append(HistoryItem.from_dict(d))
+                except Exception:
+                    continue
+            items.sort(key=lambda x: x.timestamp, reverse=True)
+            return items
         except Exception as e:
             self.logger.error(f"加载历史记录索引失败: {e}", exc_info=True)
-            _flush_logs()
             return []
 
     def get_history_item(self, timestamp: str) -> Optional[HistoryItem]:
@@ -1066,14 +1099,26 @@ class HistoryManager:
             if record_dir.exists():
                 shutil.rmtree(record_dir)
 
-            # 更新索引文件
-            history_items = self.load_history_index()
-            history_items = [item for item in history_items if item.timestamp != timestamp]
-            self._save_history_index(history_items)
+            # 直接对 raw json 操作, 避免 load_history_index O(N) 全扫
+            if not self.history_index_file.exists():
+                return True
+            try:
+                with open(self.history_index_file, 'r', encoding='utf-8') as f:
+                    raw = json.load(f)
+                if not isinstance(raw, list):
+                    raw = []
+            except Exception:
+                raw = []
+            raw = [d for d in raw if isinstance(d, dict) and d.get('timestamp') != timestamp]
+            try:
+                with open(self.history_index_file, 'w', encoding='utf-8') as f:
+                    json.dump(raw, f, ensure_ascii=False, indent=2)
+            except Exception as e:
+                self.logger.error(f"删除后写回索引失败: {e}")
 
             return True
         except Exception as e:
-            print(f"删除历史记录失败: {e}")
+            self.logger.error(f"删除历史记录失败: {e}")
             return False
 
     def _update_history_index(self, history_item: HistoryItem):
@@ -1107,40 +1152,46 @@ class HistoryManager:
         except Exception as e:
             self.logger.error(f"_update_history_index 写入索引失败: {e}")
 
-    def _save_history_index(self, history_items: List[HistoryItem]):
-        """保存历史记录索引到文件
-
-        Args:
-            history_items: 历史记录项列表
-        """
-        try:
-            data = [item.to_dict() for item in history_items]
-            with open(self.history_index_file, 'w', encoding='utf-8') as f:
-                json.dump(data, f, ensure_ascii=False, indent=2)
-        except Exception as e:
-            print(f"保存历史记录索引失败: {e}")
-
     def _cleanup_old_records(self):
         """清理旧的历史记录，保持最大数量限制。max_history_count <= 0 表示不限制。"""
         if self.max_history_count <= 0:
             return
-        history_items = self.load_history_index()
-        if len(history_items) > self.max_history_count:
-            # 保留最新的记录
-            items_to_keep = history_items[:self.max_history_count]
-            items_to_remove = history_items[self.max_history_count:]
-
-            # 删除多余记录的文件
-            for item in items_to_remove:
-                record_dir = self.base_path / item.timestamp
-                if record_dir.exists():
-                    try:
-                        shutil.rmtree(record_dir)
-                    except Exception as e:
-                        print(f"删除旧历史记录失败 {item.timestamp}: {e}")
+        if not self.history_index_file.exists():
+            return
+        try:
+            with open(self.history_index_file, 'r', encoding='utf-8') as f:
+                raw = json.load(f)
+            if not isinstance(raw, list):
+                return
+        except Exception as e:
+            self.logger.error(f"_cleanup_old_records 读取索引失败: {e}")
+            return
+
+        # 倒序排列，保留前 N 条
+        raw.sort(key=lambda d: d.get('timestamp', '') if isinstance(d, dict) else '', reverse=True)
+        if len(raw) <= self.max_history_count:
+            return
+        keep = raw[:self.max_history_count]
+        remove = raw[self.max_history_count:]
+
+        for d in remove:
+            if not isinstance(d, dict):
+                continue
+            ts = d.get('timestamp')
+            if not ts:
+                continue
+            record_dir = self.base_path / ts
+            if record_dir.exists():
+                try:
+                    shutil.rmtree(record_dir)
+                except Exception as e:
+                    self.logger.warning(f"删除旧记录失败 {ts}: {e}")
 
-            # 更新索引文件
-            self._save_history_index(items_to_keep)
+        try:
+            with open(self.history_index_file, 'w', encoding='utf-8') as f:
+                json.dump(keep, f, ensure_ascii=False, indent=2)
+        except Exception as e:
+            self.logger.error(f"_cleanup_old_records 写回索引失败: {e}")
 
 
 class LoginDialog(QDialog):