fix(server): 兼容模型 tasks 输出为 JSON 字符串与 flow_id 误填

- StewardModelPlanBuilder 解析 tasks 时兼容模型把数组序列化为字符串的情况，先反序列化；JSON 截断/语法不完整时用正则抢救 task_type/requested_action/ontology_fields 等关键字段
- task_type 未命中意图时尝试 flow_id→task_type 映射还原，避免模型把 flow_id（如 travel_application）误填为 task_type 导致正确意图被丢弃

server/src/app/services/steward_model_plan_builder.py

@@ -1,5 +1,6 @@
 from __future__ import annotations
 
+import json
 import re
 import uuid
 from datetime import date
@@ -110,6 +111,19 @@ class StewardModelPlanBuilder:
         base_date: date,
     ) -> list[StewardTask]:
         raw_tasks = payload.get("tasks")
+        # 兼容模型把 tasks 输出成 JSON 字符串(而非数组)的情况:
+        # 某些供应商在流式输出时会把整个数组序列化为字符串,需要先反序列化。
+        if isinstance(raw_tasks, str):
+            raw_tasks = raw_tasks.strip()
+            if not raw_tasks:
+                return []
+            try:
+                parsed_tasks = json.loads(raw_tasks)
+            except (TypeError, ValueError):
+                # JSON 可能被截断或语法不完整,尝试从残缺字符串里抢救 task_type 等关键字段,
+                # 避免模型偶发的格式抖动导致正确意图被整体丢弃。
+                parsed_tasks = self._salvage_tasks_from_fragment(raw_tasks)
+            raw_tasks = parsed_tasks if isinstance(parsed_tasks, list) else []
         if not isinstance(raw_tasks, list):
             return []
 
@@ -119,6 +133,13 @@ class StewardModelPlanBuilder:
                 continue
             task_type = str(raw_task.get("task_type") or "").strip()
             intent_descriptor = get_intent(task_type)
+            if intent_descriptor is None:
+                # 兼容模型把 flow_id(如 travel_application)误填为 task_type 的情况:
+                # 通过 flow_id → task_type 映射还原,避免正确意图被丢弃。
+                mapped_task_type = resolve_task_type_for_flow(task_type)
+                if mapped_task_type is not None:
+                    task_type = mapped_task_type
+                    intent_descriptor = get_intent(task_type)
             if intent_descriptor is None:
                 continue
 
@@ -188,6 +209,50 @@ class StewardModelPlanBuilder:
 
         return tasks
 
+    @staticmethod
+    def _salvage_tasks_from_fragment(fragment: str) -> list[dict[str, Any]]:
+        """从残缺的 JSON 字符串里抢救 task 结构,避免模型格式抖动导致意图被整体丢弃。
+
+        模型偶发把 tasks 输出成被截断或语法不完整的 JSON 字符串,直接 json.loads 会失败。
+        这里用正则提取 task_type、requested_action 和 ontology_fields 等关键字段,
+        构造最小可用的 task dict 列表。
+        """
+        if not fragment:
+            return []
+        task_type_match = re.search(r'"task_type"\s*:\s*"([^"]+)"', fragment)
+        if not task_type_match:
+            return []
+        task_type = task_type_match.group(1).strip()
+        requested_action = "preview"
+        action_match = re.search(r'"requested_action"\s*:\s*"([^"]+)"', fragment)
+        if action_match:
+            requested_action = action_match.group(1).strip()
+
+        # 提取 ontology_fields 对象内的键值对
+        ontology_fields: dict[str, str] = {}
+        ontology_block = re.search(
+            r'"ontology_fields"\s*:\s*\{([^}]*)\}',
+            fragment,
+        )
+        if ontology_block:
+            for key_match in re.finditer(
+                r'"([^"]+)"\s*:\s*"([^"]*)"',
+                ontology_block.group(1),
+            ):
+                ontology_fields[key_match.group(1)] = key_match.group(2)
+
+        title_match = re.search(r'"title"\s*:\s*"([^"]+)"', fragment)
+        summary_match = re.search(r'"summary"\s*:\s*"([^"]+)"', fragment)
+        return [{
+            "task_type": task_type,
+            "title": title_match.group(1) if title_match else "",
+            "summary": summary_match.group(1) if summary_match else "",
+            "confidence": 0.8,
+            "requested_action": requested_action,
+            "ontology_fields": ontology_fields,
+            "missing_fields": [],
+        }]
+
     def _build_pending_flow_confirmation(
         self,
         payload: dict[str, Any],