refactor(api): 请求体解析收成 readJson / parseBody

54 处 handler 都手写同一段：
  const parsed = X.safeParse(await c.req.json().catch(() => null))
  if (!parsed.success) return failure(c, 400, "invalid-request", ...)
漏写 .catch 就是一个畸形请求打出 500。

- http.ts 加 readJson（读 + 校验）和 parseBody（再加上 400）。parseBody 不给
  message 时回 zod 的第一条 issue —— 后台表单原来就是这么写的，fallback 文案
  「Invalid payload」/「参数错误」只在 issues 为空时才用得上，实际走不到
- 51 处换成 parseBody；另 3 处失败时带别的错误码或和路径参数一起判，换成 readJson
- 错误码、状态码、文案、判断顺序都不变

实跑核过：非 JSON 请求体回原来的固定文案，公告标题为空回 zod issue。

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

apps/api/src/routes/account.ts

@@ -43,7 +43,7 @@ import { onlineUserIds } from "../auth/presence"
 import { optionalAuth, requireAuth, type AppEnv } from "../auth/middleware"
 import { config } from "../config"
 import { db, schema } from "../db"
-import { failure, success } from "../http"
+import { failure, parseBody, success } from "../http"
 import { JudgeStatus } from "../judge/status"
 import { getBooleanOption } from "../services/options"
 import { getUserProfileById } from "../services/profile"
@@ -70,11 +70,12 @@ export const accountRoutes = new Hono<AppEnv>()
 const REGISTER_PER_IP: AttemptRule = { limit: 100, windowSeconds: 60 * 60 }
 
 accountRoutes.post("/users", async (c) => {
-  const parsed = registerRequestSchema.safeParse(
-    await c.req.json().catch(() => null),
+  const parsed = await parseBody(
+    c,
+    registerRequestSchema,
+    "Invalid registration payload",
   )
-  if (!parsed.success)
-    return failure(c, 400, "invalid-request", "Invalid registration payload")
+  if (!parsed.success) return parsed.response
   if (!(await getBooleanOption("allow_register", true))) {
     return failure(
       c,
@@ -173,11 +174,12 @@ accountRoutes.get("/profiles/:username", optionalAuth, async (c) => {
 })
 
 accountRoutes.put("/me/profile", requireAuth, async (c) => {
-  const parsed = updateProfileRequestSchema.safeParse(
-    await c.req.json().catch(() => null),
+  const parsed = await parseBody(
+    c,
+    updateProfileRequestSchema,
+    "Invalid profile payload",
   )
-  if (!parsed.success)
-    return failure(c, 400, "invalid-request", "Invalid profile payload")
+  if (!parsed.success) return parsed.response
   const values = Object.fromEntries(
     Object.entries(parsed.data).map(([key, value]) => [
       key,