feat(proxy): T-P7 管理面前端（ProxyView 三卡片 + 路由/NAV 注册）

- webapp/api：getProxyStats/getProxyLedger/listProxyStudents/createStudent/
  topup/issueKey/revokeKey 封装
- ProxyView.vue 三卡片：① 命中率-毛利看板（h_g/h_p/综合/收入/成本/毛利/分桶）
  ② 学生与 key 管理（建学生/签发（明文仅显一次警示）/充值/选中签发）
  ③ 用量流水表（时间/模型/状态徽标/收入/成本/毛利）
- App.vue NAV + router 注册 /proxy；npm run build 产物更新
- 全量 423 passed

webapp/src/api/index.ts

@@ -543,6 +543,87 @@ export function watchAgent(requestId: string) {
   }
 }
 
+// ── 代理层管理面（T-P7） ─────────────────────────────────────────────────────
+
+export interface ProxyStats {
+  requests: number
+  h_g: number
+  h_p: number
+  revenue_milli: number
+  cost_milli: number
+  margin_milli: number
+  by_bucket?: Record<string, { requests: number; revenue_milli: number; cost_milli: number }>
+}
+
+export interface ProxyLedgerRow {
+  request_id: string
+  ts: number
+  model: string
+  bucket: string
+  charged_milli: number
+  upstream_cost_milli: number
+  margin_milli: number
+  status: string
+}
+
+export interface ProxyStudent {
+  id: number
+  name: string
+  class: string
+  status: string
+  balance_milli: number
+}
+
+/** GET /proxy/admin/stats：命中率-毛利看板 */
+export async function getProxyStats() {
+  const { data } = await http.get<ProxyStats>('/proxy/admin/stats')
+  return data
+}
+
+/** GET /proxy/admin/ledger：流水分页 */
+export async function getProxyLedger(studentId = 0, limit = 50, offset = 0) {
+  const { data } = await http.get<ProxyLedgerRow[]>('/proxy/admin/ledger',
+    { params: { student_id: studentId || undefined, limit, offset } })
+  return data
+}
+
+/** GET /proxy/admin/students：学生列表（后端暂 501 时返回空） */
+export async function listProxyStudents() {
+  try {
+    const { data } = await http.get<ProxyStudent[]>('/proxy/admin/students')
+    return data
+  } catch {
+    return [] as ProxyStudent[]
+  }
+}
+
+/** POST /proxy/admin/students：建学生 */
+export async function createProxyStudent(name: string, balanceYuan: number, klass = '') {
+  const { data } = await http.post('/proxy/admin/students',
+    { name, class: klass, balance_yuan: balanceYuan })
+  return data as unknown as ProxyStudent & { student_id: number }
+}
+
+/** POST /proxy/admin/students/{id}/topup：充值 */
+export async function topupProxyStudent(id: number, amountYuan: number) {
+  const { data } = await http.post<{ ok: boolean; balance_milli: number }>(
+    `/proxy/admin/students/${id}/topup`, { amount_yuan: amountYuan })
+  return data
+}
+
+/** POST /proxy/admin/keys：签发 key（明文只返回一次） */
+export async function issueProxyKey(studentId: number) {
+  const { data } = await http.post<{ key_id: number; key: string; prefix: string }>(
+    '/proxy/admin/keys', { student_id: studentId })
+  return data
+}
+
+/** POST /proxy/admin/keys/{id}/revoke：注销 */
+export async function revokeProxyKey(keyId: number) {
+  const { data } = await http.post<{ ok: boolean }>(`/proxy/admin/keys/${keyId}/revoke`)
+  return data
+}
+
 // ── 辅助：轮询直到完成（用于不需要 SSE 的场景）──────────────────────────────────
 
 export async function pollUntilDone(