fix: 审批流修复 + 通知KeyError修复

审批流修复:
- 提交阶段(step_type=submit)自动approved，不再创建pending记录
- 审批权限添加auditor角色(require_role admin/dba/auditor)
- 审批完成判断排除execute步骤(step_type!=execute才计入has_next)
- review_ticket中加载workflow_steps用于step_type判断
- Ticket字段名修正: creator_id -> applicant_id

通知修复:
- send()中自动补充sql_preview字段(sql_content前100字符)
- 飞书/钉钉模板format改为format_map+安全fallback(缺失字段不报KeyError)
- DB中auditor用户role从developer修正为auditor

测试: 1182 passed, 0 failed
审批流全链路验证通过: 提交->DBA审核->审计员审核->admin执行->success

backend/app/services/notification_sender.py

@@ -125,6 +125,11 @@ class NotificationSender:
         # 通知脱敏：隐藏 SQL 中的敏感内容
         data = self._mask_sensitive_data(data)
 
+        # 自动补充 sql_preview（取 sql_content 前100字符）
+        if "sql_preview" not in data and "sql_content" in data:
+            sql = data["sql_content"]
+            data["sql_preview"] = sql[:100] + ("..." if len(sql) > 100 else "")
+
         try:
             if channel_type == "dingtalk":
                 return await self._send_dingtalk(config, event_type, data)
@@ -158,8 +163,15 @@ class NotificationSender:
                 webhook_url = f"{webhook_url}?timestamp={timestamp}&sign={sign}"
 
         template = self.TEMPLATES.get(event_type, self.TEMPLATES["ticket_created"])
-        title = template["title"].format(**data)
-        body = template["body"].format(**data)
+        # 安全格式化
+        safe_data = {**data}
+        for key in ["applicant", "ticket_id", "title", "db_type", "instance_name",
+                     "target_database", "sql_content", "sql_preview", "approver",
+                     "comment", "result", "duration", "affected_rows", "error",
+                     "operator", "database", "size", "drift_count", "drift_details"]:
+            safe_data.setdefault(key, "")
+        title = template["title"].format_map(safe_data)
+        body = template["body"].format_map(safe_data)
         tag = self.DINGTALK_TAGS.get(event_type, "📌")
 
         # 钉钉 markdown 单个 \n 视为空格，需要 \n\n 才能换行
@@ -191,8 +203,15 @@ class NotificationSender:
             return {"success": False, "message": "缺少 webhook_url 配置"}
 
         template = self.TEMPLATES.get(event_type, self.TEMPLATES["ticket_created"])
-        title = template["title"].format(**data)
-        body = template["body"].format(**data)
+        # 安全格式化：缺失字段用空字符串代替，避免 KeyError
+        safe_data = {**data}
+        for key in ["applicant", "ticket_id", "title", "db_type", "instance_name",
+                     "target_database", "sql_content", "sql_preview", "approver",
+                     "comment", "result", "duration", "affected_rows", "error",
+                     "operator", "database", "size", "drift_count", "drift_details"]:
+            safe_data.setdefault(key, "")
+        title = template["title"].format_map(safe_data)
+        body = template["body"].format_map(safe_data)
         color = self.FEISHU_COLORS.get(event_type, "blue")
 
         payload = {