chore(阶段3): 删除阶段 1 的临时验证物

GET /api/dev/problems、dev-problems.vue、对应路由项，以及只服务于它的
problemSummarySchema。阶段 1 用来验证「能从真实库读出一道题」，已完成使命。

Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>

apps/web/src/routes.ts

@@ -5,7 +5,6 @@ export const ojs: RouteRecordRaw = {
   component: () => import("shared/layout/default.vue"),
   children: [
     { path: "", component: () => import("oj/problem/list.vue") },
-    { path: "dev-problems", component: () => import("oj/dev-problems.vue") },
     {
       path: "problem/:problemID",
       component: () => import("oj/problem/detail.vue"),