fix: audit_logs 表缺少 iteration 列导致写入失败

- CREATE TABLE 加入 iteration INTEGER
- 新增迁移 ALTER TABLE audit_logs ADD COLUMN iteration

electron/services/database.service.ts

@@ -121,6 +121,7 @@ export class DatabaseService {
       CREATE TABLE IF NOT EXISTS audit_logs (
         id              INTEGER PRIMARY KEY AUTOINCREMENT,
         session_id      TEXT,
+        iteration       INTEGER,
         event_type      TEXT NOT NULL,
         actor           TEXT NOT NULL DEFAULT 'system',
         target          TEXT NOT NULL,
@@ -229,6 +230,14 @@ export class DatabaseService {
     } catch {
       // 列已存在，忽略
     }
+
+    // 迁移 2: audit_logs 表添加 iteration 列
+    try {
+      db.exec('ALTER TABLE audit_logs ADD COLUMN iteration INTEGER');
+      log.info('[DB] Migration: added iteration column to audit_logs');
+    } catch {
+      // 列已存在，忽略
+    }
   }
 
   /**