feat(阶段3): oj 侧端点铺开（基线提交，未经评审）

由外部 agent (Codex) 在本会话额度中断期间完成。原样提交作为基线，
后续修复单独成 commit，便于区分与回退。

覆盖 oj 侧 65 个端点，新增 9 组路由（account/achievement/ai/classroom/
content/contest/flowchart/problemset/site）与对应 Zod 契约。

已核验：tsc --noEmit 退出码 0；API 可启动；/api/problems 返回真实数据；
judge 与 flowchart worker 均 ready。
未核验：权限边界与数据泄露，评审进行中。

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

apps/api/src/index.ts

@@ -1,11 +1,21 @@
 import { Hono } from "hono"
+import { basename, resolve } from "node:path"
 
 import { getRequestSessionUser } from "./auth/session"
 import { config } from "./config"
 import { authRoutes } from "./routes/auth"
+import { accountRoutes } from "./routes/account"
 import { judgeServerRoutes } from "./routes/judge-server"
+import { contestRoutes } from "./routes/contest"
+import { contentRoutes } from "./routes/content"
+import { classroomRoutes } from "./routes/classroom"
+import { problemsetRoutes } from "./routes/problemset"
+import { achievementRoutes } from "./routes/achievement"
+import { aiRoutes } from "./routes/ai"
+import { flowchartRoutes } from "./routes/flowchart"
 import { problemRoutes } from "./routes/problem"
 import { submissionRoutes } from "./routes/submission"
+import { siteRoutes } from "./routes/site"
 import {
   bridgeSubmissionEvents,
   submissionWebSocketHandler,
@@ -16,6 +26,15 @@ const app = new Hono()
 
 app.get("/health", (c) => c.json({ ok: true }))
 app.route("/api", authRoutes)
+app.route("/api", accountRoutes)
+app.route("/api", siteRoutes)
+app.route("/api", contestRoutes)
+app.route("/api", contentRoutes)
+app.route("/api", classroomRoutes)
+app.route("/api", problemsetRoutes)
+app.route("/api", achievementRoutes)
+app.route("/api", aiRoutes)
+app.route("/api", flowchartRoutes)
 app.route("/api", problemRoutes)
 app.route("/api", submissionRoutes)
 app.route("/api", judgeServerRoutes)
@@ -32,6 +51,21 @@ const server = Bun.serve<SubmissionSocketData>({
 	port: config.port,
 	async fetch(request, bunServer) {
 		const url = new URL(request.url)
+		if (url.pathname.startsWith(`${config.avatarUriPrefix}/`)) {
+			const filename = basename(decodeURIComponent(url.pathname))
+			if (filename !== decodeURIComponent(url.pathname).split("/").at(-1)) {
+				return new Response("Not found", { status: 404 })
+			}
+			const file = Bun.file(resolve(config.avatarDirectory, filename))
+			if (await file.exists()) return new Response(file)
+			if (filename === "default.png") {
+				return new Response(
+					'<svg xmlns="http://www.w3.org/2000/svg" viewBox="0 0 128 128"><rect width="128" height="128" rx="64" fill="#e2e8f0"/><circle cx="64" cy="48" r="24" fill="#94a3b8"/><path d="M20 120c4-28 22-42 44-42s40 14 44 42" fill="#94a3b8"/></svg>',
+					{ headers: { "content-type": "image/svg+xml", "cache-control": "public, max-age=3600" } },
+				)
+			}
+			return new Response("Not found", { status: 404 })
+		}
 		if (url.pathname === "/ws/submissions") {
 			const user = await getRequestSessionUser(request)
 			if (!user) return new Response("Unauthorized", { status: 401 })