feat(admin): 租户页加「共享计费」开关（每租户）

TenantRow 带 shared_billing；选定租户成员区上方加共享计费开关（PUT
/admin/tenants/:id/shared-billing）：开=成员消耗计本租户池、关=各计个人池。
live 验证：公司A 开关随真实状态回显为勾选。

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

sundynix-admin/src/api.ts

@@ -447,6 +447,7 @@ export interface TenantRow {
   plan: string;
   status: string;
   credit_balance_micro: number;
+  shared_billing: boolean;
   members: number;
 }
 export interface Member {
@@ -500,3 +501,11 @@ export async function removeMember(tenantId: string, uid: string): Promise<void>
     throw new Error(d.error ?? `remove member failed: ${res.status}`);
   }
 }
+
+export async function setSharedBilling(tenantId: string, on: boolean): Promise<void> {
+  const res = guard(await fetch(`${ADMIN}/tenants/${tenantId}/shared-billing`, { method: "PUT", headers: authHeaders(true), body: JSON.stringify({ shared_billing: on }) }));
+  if (!res.ok) {
+    const d = (await res.json().catch(() => ({}))) as { error?: string };
+    throw new Error(d.error ?? `set shared billing failed: ${res.status}`);
+  }
+}

sundynix-admin/src/pages/TenantsPage.tsx

@@ -1,5 +1,5 @@
 import { useEffect, useMemo, useState } from "react";
-import { listTenants, createTenant, listMembers, addMember, setMemberRole, removeMember, type TenantRow, type Member } from "../api";
+import { listTenants, createTenant, listMembers, addMember, setMemberRole, removeMember, setSharedBilling, type TenantRow, type Member } from "../api";
 
 // 管理端「租户 & 用户」= 多成员租户管理（平台运维口径）：租户目录 + 每租户成员增改删。
 // 全真数据：GET/POST /admin/tenants、/admin/tenants/:id/members。
@@ -110,6 +110,14 @@ export function TenantsPage() {
       setMErr((e as Error).message);
     }
   };
+  const onToggleShared = async (on: boolean) => {
+    try {
+      await setSharedBilling(selId, on);
+      await loadTenants();
+    } catch (e) {
+      setMErr((e as Error).message);
+    }
+  };
 
   if (loading) return <div className="text-sm text-gray-400">加载租户中…</div>;
 
@@ -172,6 +180,13 @@ export function TenantsPage() {
                   <span className="tabular-nums text-xs text-gray-500">{credits(selected.credit_balance_micro)} 积分</span>
                 </div>
 
+                {/* 共享计费开关 */}
+                <label className="mb-3 flex cursor-pointer items-center gap-2 rounded-lg border border-gray-100 bg-gray-50/50 px-3 py-2 text-xs text-gray-600">
+                  <input type="checkbox" checked={selected.shared_billing} onChange={(e) => void onToggleShared(e.target.checked)} className="h-4 w-4 accent-violet-600" />
+                  <span className="font-medium text-gray-700">共享计费</span>
+                  <span className="text-gray-400">开：成员消耗计本租户积分池；关：成员各计个人池（owner 恒计本租户）</span>
+                </label>
+
                 {/* 加成员 */}
                 <div className="mb-4 flex flex-wrap items-center gap-2 rounded-lg border border-violet-100 bg-violet-50/30 p-3">
                   <input className="flex-1 rounded border bg-white px-2 py-1.5 text-xs focus:border-violet-500 focus:outline-none" placeholder="按邮箱加入已注册用户" value={mEmail} onChange={(e) => setMEmail(e.target.value)} />