feat(billing): 人工退款入口 —— paid 单冲销积分+置 refunded(幂等)

PAYMENT_DESIGN §5 承诺却只留了 OrderRefunded 常量、无入口。补齐全链路:

- store.RefundOrder:订单 CAS(paid→refunded) 为主闸(重复退 changed=false 幂等),
  同事务记 adjust 负分录(ref=订单号)+ 回退物化余额。照抄 MarkOrderPaid 双闸范式;
  新增 idx_ledger_refund_ref 部分唯一索引(kind='adjust' AND ref<>'')做账本级兜底,
  与 grant 索引对称、不与 admin 手工校正(ref 空)冲突。
- 积分若已消费,回退后余额可为负(人工退款预期,账本仍自洽,后续消费被硬拦截)。
- handler AdminRefundOrder + POST /admin/orders/:id/refund(admin 组已挂 Audit 留痕);
  真渠道钱款原路退回需 admin 另在商户后台操作,本地仅冲销积分与订单态(不接自动退款 API)。
- admin 订单流加「退款」按钮(仅 paid 单可见,二次确认+填原因)。
- 测试:RefundOrder 冲销+幂等、只退 paid 两个不变量测试(sqlite 真 DB,余额=账本之和)。
  gateway build/vet/test 全绿,admin tsc 干净。

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

sundynix-admin/src/api.ts

@@ -301,6 +301,19 @@ export async function adminReconcile(): Promise<{ diffs: ReconcileDiff[]; ok: bo
   return { diffs: d.diffs ?? [], ok: !!d.ok };
 }
 
+// 人工退款：仅对已入账(paid)单——置 refunded + 记 adjust 负分录 + 回退余额（幂等）。
+// status="noop" 表示该单本就无需退（已退/未支付）。真渠道钱的原路退回需 admin 另在商户后台操作。
+export async function adminRefundOrder(id: string, memo: string): Promise<{ status: string; detail?: string }> {
+  const res = guard(await fetch(`${ADMIN}/orders/${id}/refund`, {
+    method: "POST",
+    headers: { ...authHeaders(), "Content-Type": "application/json" },
+    body: JSON.stringify({ memo }),
+  }));
+  const d = (await res.json().catch(() => ({}))) as { status?: string; detail?: string; error?: string };
+  if (!res.ok) throw new Error(d.error ?? `refund failed: ${res.status}`);
+  return { status: d.status ?? "", detail: d.detail };
+}
+
 // ---- 自动评测观测（真数据，来自 sundynix_eval）----
 export interface EvalDay {
   day: string; // YYYYMMDD

sundynix-admin/src/components/OrderStream.tsx

@@ -1,5 +1,5 @@
 import { useCallback, useEffect, useState } from "react";
-import { adminOrders, adminReconcile, type PayOrder, type OrderStats, type ReconcileDiff } from "../api";
+import { adminOrders, adminReconcile, adminRefundOrder, type PayOrder, type OrderStats, type ReconcileDiff } from "../api";
 
 // 充值订单流 + 日终对账（P5.3 观测）。全平台充值单的落地视角：
 //   - 状态计数卡片（pending/paid/expired + 累计到账额）
@@ -27,6 +27,7 @@ export function OrderStream() {
   // 对账结果：null=未跑；[]=零差异；有元素=有差异
   const [diffs, setDiffs] = useState<ReconcileDiff[] | null>(null);
   const [checking, setChecking] = useState(false);
+  const [refunding, setRefunding] = useState(""); // 正在退款的订单 id
 
   const load = useCallback(() => {
     adminOrders(filter)
@@ -51,6 +52,27 @@ export function OrderStream() {
     }
   };
 
+  const refund = async (o: PayOrder) => {
+    // 退款不可逆（冲销积分、订单置 refunded），且真渠道钱需另在商户后台原路退——二次确认 + 留原因。
+    const memo = window.prompt(
+      `确认退款？将冲销 ${credits(o.credits_micro)} 积分并把订单置为已退款（余额可能因积分已消费而变负）。\n` +
+        `注意：微信真单的钱款原路退回需另在商户后台操作，此处仅冲销本地积分与订单态。\n\n请填写退款原因：`,
+      "",
+    );
+    if (memo === null) return; // 取消
+    setRefunding(o.id);
+    setErr("");
+    try {
+      const r = await adminRefundOrder(o.id, memo);
+      if (r.status === "noop") setErr(r.detail ?? "该订单无需退款");
+      load();
+    } catch (e) {
+      setErr((e as Error).message);
+    } finally {
+      setRefunding("");
+    }
+  };
+
   return (
     <div className="space-y-4">
       <div className="flex items-center gap-2 pt-1">
@@ -117,7 +139,8 @@ export function OrderStream() {
                 <th className="py-2 pr-3 font-medium">渠道</th>
                 <th className="py-2 pr-3 text-right font-medium">积分</th>
                 <th className="py-2 pr-3 text-right font-medium">金额</th>
-                <th className="py-2 font-medium">状态</th>
+                <th className="py-2 pr-3 font-medium">状态</th>
+                <th className="py-2 text-right font-medium">操作</th>
               </tr>
             </thead>
             <tbody>
@@ -128,16 +151,26 @@ export function OrderStream() {
                   <td className="py-1.5 pr-3 text-xs text-gray-500">{CHANNEL_LABEL[o.channel] ?? o.channel}</td>
                   <td className="py-1.5 pr-3 text-right tabular-nums text-gray-800">{credits(o.credits_micro)}</td>
                   <td className="py-1.5 pr-3 text-right tabular-nums text-gray-500">{o.amount_fen > 0 ? yuan(o.amount_fen) : "—"}</td>
-                  <td className="py-1.5">
+                  <td className="py-1.5 pr-3">
                     <span className={`rounded px-1.5 py-0.5 text-[10px] ${STATUS_BADGE[o.status] ?? "bg-gray-100 text-gray-500"}`}>
                       {STATUS_LABEL[o.status] ?? o.status}
                     </span>
                   </td>
+                  <td className="py-1.5 text-right">
+                    {o.status === "paid" ? (
+                      <button onClick={() => void refund(o)} disabled={refunding === o.id}
+                        className="rounded border border-rose-200 px-2 py-0.5 text-[11px] text-rose-600 hover:bg-rose-50 disabled:opacity-40">
+                        {refunding === o.id ? "退款中…" : "退款"}
+                      </button>
+                    ) : (
+                      <span className="text-[11px] text-gray-300">—</span>
+                    )}
+                  </td>
                 </tr>
               ))}
               {orders.length === 0 && (
                 <tr>
-                  <td colSpan={6} className="py-6 text-center text-xs text-gray-400">暂无充值订单</td>
+                  <td colSpan={7} className="py-6 text-center text-xs text-gray-400">暂无充值订单</td>
                 </tr>
               )}
             </tbody>