feat: 小财管家意图规划与报销提交编排增强

- 完善管家意图识别、模型计划构建与规划器调度
- 重构差旅报销提交编排器与管家计划流程前端交互
- 优化报销消息项样式与文档中心视图
- 新增小财管家与附件上传风险前置复核设计文档
- 补充管家规划器与文档中心测试覆盖

server/src/app/api/v1/endpoints/steward.py

@@ -11,7 +11,7 @@ from sqlalchemy.orm import Session
 
 from app.api.deps import get_db
 from app.schemas.common import ErrorResponse
-from app.schemas.steward import StewardPlanRequest, StewardPlanResponse
+from app.schemas.steward import StewardPlanRequest, StewardPlanResponse, StewardThinkingEvent
 from app.services.runtime_chat import RuntimeChatService
 from app.services.steward_intent_agent import StewardIntentAgent
 from app.services.steward_planner import StewardPlannerService
@@ -55,6 +55,18 @@ async def _iter_steward_plan_events(
     payload: StewardPlanRequest,
     planner: StewardPlannerService,
 ) -> AsyncIterator[str]:
+    yield _encode_stream_event(
+        "thinking",
+        StewardThinkingEvent(
+            event_id="intent_agent_stream_start",
+            stage="stream_start",
+            title="意图识别智能体接管",
+            content="已收到任务描述，正在调用小财管家意图识别智能体拆解申请、报销和附件线索。",
+            status="running",
+        ).model_dump(mode="json"),
+    )
+    await asyncio.sleep(0)
+
     try:
         plan = planner.build_plan(payload)
     except ValueError as exc: