feat: 增加差旅报销标准测算和财务终审流程

新增差旅报销测算接口及 Spreadsheet 规则解析，审批流程拆分
直属领导审批与财务终审两阶段并细分权限，修复 PDF 文本层
缺失时自动回退 OCR，提交后清理关联会话，前端适配审批流
交互并补充单元测试。

server/src/app/services/agent_conversations.py

@@ -39,6 +39,7 @@ class AgentConversationService:
         normalized_id = str(conversation_id or "").strip()
         normalized_user_id = str(user_id or "").strip() or None
         incoming_session_type = str(context_json.get("session_type") or "").strip() or "expense"
+        incoming_draft_claim_id = self._resolve_draft_claim_id(context_json)
         conversation = self.get_conversation(normalized_id) if normalized_id else None
         if conversation is not None and conversation.user_id != normalized_user_id:
             normalized_id = ""
@@ -56,6 +57,7 @@ class AgentConversationService:
                 source=source,
                 entry_source=str(context_json.get("entry_source") or "").strip() or None,
                 title=self._resolve_title(context_json),
+                draft_claim_id=incoming_draft_claim_id or None,
                 state_json=self._extract_state_json(context_json),
             )
             self.db.add(conversation)
@@ -69,6 +71,8 @@ class AgentConversationService:
             conversation.entry_source = str(context_json.get("entry_source") or "").strip() or None
         if not conversation.title:
             conversation.title = self._resolve_title(context_json)
+        if incoming_draft_claim_id:
+            conversation.draft_claim_id = incoming_draft_claim_id
         conversation.state_json = self._merge_state_json(
             conversation.state_json,
             self._extract_state_json(context_json),
@@ -354,6 +358,38 @@ class AgentConversationService:
         self.db.commit()
         return len(conversations)
 
+    def delete_conversations_for_draft_claim(
+        self,
+        *,
+        claim_id: str | None,
+        source: str | None = "user_message",
+        session_type: str | None = "expense",
+    ) -> int:
+        normalized_claim_id = str(claim_id or "").strip()
+        if not normalized_claim_id:
+            return 0
+
+        stmt = select(AgentConversation).where(AgentConversation.draft_claim_id == normalized_claim_id)
+        if source:
+            stmt = stmt.where(AgentConversation.source == source)
+        conversations = list(self.db.scalars(stmt).all())
+        normalized_session_type = str(session_type or "").strip()
+        if normalized_session_type:
+            conversations = [
+                conversation
+                for conversation in conversations
+                if (str((conversation.state_json or {}).get("session_type") or "").strip() or "expense")
+                == normalized_session_type
+            ]
+        if not conversations:
+            return 0
+
+        for conversation in conversations:
+            self.db.delete(conversation)
+
+        self.db.commit()
+        return len(conversations)
+
     def delete_conversation(
         self,
         *,
@@ -478,11 +514,28 @@ class AgentConversationService:
                 continue
             state_json[key] = value
 
-        draft_claim_id = str(context_json.get("draft_claim_id") or "").strip()
+        draft_claim_id = AgentConversationService._resolve_draft_claim_id(context_json)
         if draft_claim_id:
             state_json["draft_claim_id"] = draft_claim_id
         return state_json
 
+    @staticmethod
+    def _resolve_draft_claim_id(context_json: dict[str, Any]) -> str:
+        draft_claim_id = str((context_json or {}).get("draft_claim_id") or "").strip()
+        if draft_claim_id:
+            return draft_claim_id
+
+        request_context = (context_json or {}).get("request_context")
+        if isinstance(request_context, dict):
+            return str(
+                request_context.get("claim_id")
+                or request_context.get("claimId")
+                or request_context.get("draft_claim_id")
+                or request_context.get("draftClaimId")
+                or ""
+            ).strip()
+        return ""
+
     @staticmethod
     def _merge_state_json(
         current_state: dict[str, Any] | None,