feat(ai): unify verified expense application workflow

server/src/app/schemas/steward.py

@@ -160,7 +160,16 @@ class StewardActionExecuteRequest(BaseModel):
     action_step: StewardActionStep | None = Field(default=None, description="规划侧生成的动作步骤快照。")
     confirmed: bool = Field(default=False, description="用户是否已确认执行该动作。")
     context_json: dict[str, Any] = Field(default_factory=dict, description="前端或运行时补充上下文。")
-    client_trace_id: str = Field(default="", description="前端幂等或追踪 ID。")
+    client_trace_id: str = Field(
+        default="",
+        max_length=120,
+        description="前端稳定幂等 ID；申请预览签发、保存和提交动作必须显式提供。",
+    )
+    decision_id: str = Field(
+        default="",
+        max_length=36,
+        description="服务端签发的申请预览决策 ID；保存和提交申请时必须显式提供。",
+    )
 
 
 class StewardActionExecuteResponse(BaseModel):