Refine travel reimbursement steward flow

Align planner, runtime rules, and policy assets so travel guidance
matches the updated reimbursement workflow.

server/src/app/services/agent_foundation_preapproval_spreadsheet.py

@@ -0,0 +1,62 @@
+from __future__ import annotations
+
+
+def build_preapproval_rule_workbook_sheets() -> list[tuple[str, list[list[object]]]]:
+    return [
+        (
+            "费用申请审批规则",
+            [
+                [
+                    "费用类型代码",
+                    "费用类型",
+                    "触发条件",
+                    "阈值金额",
+                    "前置要求",
+                    "审批要求",
+                    "风险动作",
+                    "备注",
+                ],
+                [
+                    "meal/entertainment",
+                    "业务招待费",
+                    "单次费用金额大于 500 元",
+                    500,
+                    "必须先提交费用申请单，并说明客户、参与人和招待事由",
+                    "申请单需按审批链完成审批后方可报销",
+                    "报销阶段未关联已通过申请单时标记高风险",
+                    "适配 meal 与 entertainment 两个本体费用类型",
+                ],
+                [
+                    "office",
+                    "办公用品费",
+                    "单次或批量采购金额大于 2000 元",
+                    2000,
+                    "必须先提交办公采购或费用申请单",
+                    "申请单需经直属领导审批；如触发预算管控则继续预算复核",
+                    "报销阶段未关联已通过申请单时标记高风险",
+                    "覆盖办公用品、办公耗材、低值易耗品等场景",
+                ],
+                [
+                    "all",
+                    "通用大额费用",
+                    "任意费用金额大于 2000 元",
+                    2000,
+                    "必须进入费用申请和审批流程",
+                    "至少完成直属领导审批；按预算和基础规则继续流转",
+                    "报销阶段未关联已通过申请单时标记高风险",
+                    "差旅、通信等已有专项规则时可同时适用专项规则",
+                ],
+            ],
+        ),
+        (
+            "字段说明",
+            [
+                ["字段", "说明"],
+                ["费用类型代码", "使用系统本体费用类型，不新增非本体字段"],
+                ["阈值金额", "单位为人民币元，执行时按 claim.amount 进行数值比较"],
+                ["前置要求", "说明是否需要事前申请以及申请单需要包含的信息"],
+                ["审批要求", "说明申请单进入审批链后的最低审批要求"],
+                ["风险动作", "说明报销阶段未满足规则时的系统处理"],
+            ],
+        ),
+    ]