feat(distribution): 分站发布群只使用自己的二维码池

主站单独维护分站码池，池空时不再借用主站或其他分站，并去掉已停用的固定二维码入口。

Co-authored-by: Cursor <cursoragent@cursor.com>

frontend/src/features/admin/api/adminQrCodes.ts

@@ -170,3 +170,52 @@ export async function batchDeleteQrCodes(ids: number[]) {
   )
   return data.data
 }
+
+function siteQrCodeBase(siteId: number) {
+  return `/admin/distribution/sites/${siteId}/qrcodes`
+}
+
+export async function fetchSiteQrCodes(siteId: number, query: QrCodeListQuery = {}) {
+  const { data } = await apiClient.get<ApiResponse<PaginatedResult<ChatQrCode>>>(
+    siteQrCodeBase(siteId),
+    {
+      params: {
+        status: query.status || undefined,
+        keyword: query.keyword?.trim() || undefined,
+        page: query.page || 1,
+        limit: query.limit || 20,
+      },
+      silent: true,
+    }
+  )
+  return data.data
+}
+
+export async function fetchSiteQrCodeStats(siteId: number) {
+  const { data } = await apiClient.get<ApiResponse<QrCodeStats>>(
+    `${siteQrCodeBase(siteId)}/stats`,
+    { silent: true }
+  )
+  return data.data
+}
+
+export async function batchCreateSiteQrCodes(siteId: number, items: CreateQrCodePayload[]) {
+  const { data } = await apiClient.post<ApiResponse<ChatQrCode[]>>(
+    `${siteQrCodeBase(siteId)}/batch`,
+    { items }
+  )
+  return data.data
+}
+
+export async function updateSiteQrCode(siteId: number, id: number, payload: UpdateQrCodePayload) {
+  const { data } = await apiClient.patch<ApiResponse<null>>(
+    `${siteQrCodeBase(siteId)}/${id}`,
+    payload
+  )
+  return data.data
+}
+
+export async function deleteSiteQrCode(siteId: number, id: number) {
+  const { data } = await apiClient.delete<ApiResponse<null>>(`${siteQrCodeBase(siteId)}/${id}`)
+  return data.data
+}