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/admin/announcement.ts

@@ -9,7 +9,7 @@ import { Hono } from "hono"
 
 import { requireSuperAdmin, type AppEnv } from "../../auth/middleware"
 import { db, schema } from "../../db"
-import { failure, success } from "../../http"
+import { failure, parseBody, success } from "../../http"
 import { queryInteger, sampleUser } from "../helpers"
 
 export const adminAnnouncementRoutes = new Hono<AppEnv>()
@@ -78,17 +78,8 @@ adminAnnouncementRoutes.get("/announcements", requireSuperAdmin, async (c) => {
 })
 
 adminAnnouncementRoutes.post("/announcements", requireSuperAdmin, async (c) => {
-  const parsed = createAnnouncementRequestSchema.safeParse(
-    await c.req.json().catch(() => null),
-  )
-  if (!parsed.success) {
-    return failure(
-      c,
-      400,
-      "invalid-request",
-      parsed.error.issues[0]?.message ?? "Invalid payload",
-    )
-  }
+  const parsed = await parseBody(c, createAnnouncementRequestSchema)
+  if (!parsed.success) return parsed.response
   const now = new Date().toISOString()
   const [created] = await db
     .insert(schema.announcement)
@@ -126,17 +117,8 @@ adminAnnouncementRoutes.put(
   requireSuperAdmin,
   async (c) => {
     const id = queryInteger(c.req.param("id"), 0, { min: 1 })
-    const parsed = updateAnnouncementRequestSchema.safeParse(
-      await c.req.json().catch(() => null),
-    )
-    if (!parsed.success) {
-      return failure(
-        c,
-        400,
-        "invalid-request",
-        parsed.error.issues[0]?.message ?? "Invalid payload",
-      )
-    }
+    const parsed = await parseBody(c, updateAnnouncementRequestSchema)
+    if (!parsed.success) return parsed.response
     const updated = await db
       .update(schema.announcement)
       .set({ ...parsed.data, lastUpdateTime: new Date().toISOString() })