feat(admin): Admin V2 — Ant Design Pro 纯 SPA 重写

Next.js SSR/hydration 与 SWR fetch-on-mount 存在根本冲突：
hydration 卸载组件时 abort 的请求仍占用后端 DB 连接，
retry 循环耗尽 PostgreSQL 连接池导致后端完全卡死。

admin-v2 使用 Vite + React + antd 纯 SPA 彻底消除此问题：
- 12 页面全部完成（Login, Dashboard, Accounts, Providers, Models,
  API Keys, Usage, Relay, Config, Prompts, Logs, Agent Templates）
- ProTable + ProForm + ProLayout 统一 UI 模式
- TanStack Query + Axios + Zustand 数据层
- JWT 自动刷新 + 401 重试机制
- 全部 18 网络请求 200 OK，零 ERR_ABORTED

同时更新 troubleshooting 第 13 节和 SaaS 平台文档。

admin-v2/src/services/prompts.ts

@@ -0,0 +1,35 @@
+import request from './request'
+import type { PromptTemplate, PromptVersion, PaginatedResponse } from '@/types'
+
+export const promptService = {
+  list: (params?: Record<string, unknown>) =>
+    request.get<PaginatedResponse<PromptTemplate>>('/prompts', { params }).then((r) => r.data),
+
+  get: (name: string) =>
+    request.get<PromptTemplate>(`/prompts/${encodeURIComponent(name)}`).then((r) => r.data),
+
+  create: (data: {
+    name: string; category: string; description?: string; source?: string
+    system_prompt: string; user_prompt_template?: string
+    variables?: unknown[]; min_app_version?: string
+  }) =>
+    request.post<PromptTemplate>('/prompts', data).then((r) => r.data),
+
+  update: (name: string, data: { description?: string; status?: string }) =>
+    request.put<PromptTemplate>(`/prompts/${encodeURIComponent(name)}`, data).then((r) => r.data),
+
+  archive: (name: string) =>
+    request.delete<PromptTemplate>(`/prompts/${encodeURIComponent(name)}`).then((r) => r.data),
+
+  listVersions: (name: string) =>
+    request.get<PromptVersion[]>(`/prompts/${encodeURIComponent(name)}/versions`).then((r) => r.data),
+
+  createVersion: (name: string, data: {
+    system_prompt: string; user_prompt_template?: string
+    variables?: unknown[]; changelog?: string; min_app_version?: string
+  }) =>
+    request.post<PromptVersion>(`/prompts/${encodeURIComponent(name)}/versions`, data).then((r) => r.data),
+
+  rollback: (name: string, version: number) =>
+    request.post<PromptTemplate>(`/prompts/${encodeURIComponent(name)}/rollback/${version}`).then((r) => r.data),
+}