feat: 增强差旅报销审核流程与票据智能推理

优化本体解析和编排器的差旅场景处理能力，完善报销单草稿
保存和费用明细同步逻辑，前端报销创建页面增加行程推理和
票据审核交互，新增助手会话快照工具函数，补充单元测试。

server/src/app/services/agent_conversations.py

@@ -22,6 +22,9 @@ STATEFUL_CONTEXT_KEYS = (
     "business_time_context",
 )
 REVIEW_FLOW_CONTEXT_KEYS = {
+    "draft_claim_id",
+    "draft_claim_no",
+    "draft_status",
     "request_context",
     "attachment_names",
     "attachment_count",
@@ -131,7 +134,11 @@ class AgentConversationService:
         resolved_retention_days = retention_days or self._resolve_retention_days()
         cutoff = datetime.now(UTC) - timedelta(days=max(1, resolved_retention_days))
         stmt = select(AgentConversation).where(AgentConversation.updated_at < cutoff)
-        expired_conversations = list(self.db.scalars(stmt).all())
+        expired_conversations = [
+            conversation
+            for conversation in self.db.scalars(stmt).all()
+            if not self._is_saved_conversation(conversation)
+        ]
         if not expired_conversations:
             return 0
 
@@ -141,6 +148,13 @@ class AgentConversationService:
         self.db.commit()
         return len(expired_conversations)
 
+    @staticmethod
+    def _is_saved_conversation(conversation: AgentConversation) -> bool:
+        if str(conversation.draft_claim_id or "").strip():
+            return True
+        state_json = dict(conversation.state_json or {})
+        return bool(str(state_json.get("draft_claim_id") or "").strip())
+
     def _resolve_retention_days(self) -> int:
         try:
             settings_row, _ = SettingsService(self.db).ensure_settings_ready()
@@ -232,6 +246,9 @@ class AgentConversationService:
             context_json=merged,
             message=message,
         )
+        if not should_hydrate_review_flow:
+            for key in REVIEW_FLOW_CONTEXT_KEYS:
+                merged.pop(key, None)
 
         merged["conversation_id"] = conversation.conversation_id
         merged["conversation_history"] = self.list_message_history(
@@ -264,7 +281,12 @@ class AgentConversationService:
         context_json: dict[str, Any],
         message: str | None,
     ) -> bool:
+        if isinstance(context_json.get("expense_scene_selection"), dict):
+            return True
         if AgentConversationService._resolve_draft_claim_id(context_json):
+            compact_message = str(message or "").replace(" ", "")
+            if compact_message and any(keyword in compact_message for keyword in NEW_EXPENSE_PROMPT_KEYWORDS):
+                return False
             return True
         if str(context_json.get("review_action") or "").strip():
             return True