refactor: 提取 validation.ts 和 amap.ts，统一 API 路由校验逻辑

新增 validation.ts（用户名/密码/邮箱/内容/房间名/必填字段校验）
和 amap.ts（AMAP API key 校验），消除 7 个路由中的重复验证代码。

src/app/api/blindbox/route.ts

@@ -2,31 +2,27 @@ import { NextResponse } from "next/server";
 import { prisma } from "@/lib/prisma";
 import { requireMembership } from "@/lib/blindbox";
 import { apiHandler, ApiError, requireUserId } from "@/lib/api";
+import { validateIdeaContent, requireString } from "@/lib/validation";
 
 export const POST = apiHandler(async (req) => {
   const { roomId, userId, content } = await req.json();
 
   requireUserId(userId);
-  if (!roomId || typeof roomId !== "string") throw new ApiError("roomId 不能为空");
-  if (!content || typeof content !== "string" || content.trim().length === 0) {
-    throw new ApiError("内容不能为空");
-  }
-  if (content.trim().length > 200) throw new ApiError("内容不能超过 200 字");
+  requireString(roomId, "roomId");
+  const trimmedContent = validateIdeaContent(content);
 
   await requireMembership(roomId, userId);
 
   const idea = await prisma.blindBoxIdea.create({
-    data: { roomId, userId, content: content.trim() },
+    data: { roomId, userId, content: trimmedContent },
   });
 
   return NextResponse.json({ id: idea.id }, { status: 201 });
 });
 
 export const GET = apiHandler(async (req) => {
-  const roomId = req.nextUrl.searchParams.get("roomId");
   const userId = requireUserId(req.nextUrl.searchParams.get("userId"));
-
-  if (!roomId) throw new ApiError("缺少 roomId");
+  const roomId = requireString(req.nextUrl.searchParams.get("roomId"), "roomId");
 
   await requireMembership(roomId, userId);
 
@@ -56,11 +52,8 @@ export const PUT = apiHandler(async (req) => {
   const { ideaId, userId, content } = await req.json();
 
   requireUserId(userId);
-  if (!ideaId) throw new ApiError("缺少 ideaId");
-  if (!content || typeof content !== "string" || content.trim().length === 0) {
-    throw new ApiError("内容不能为空");
-  }
-  if (content.trim().length > 200) throw new ApiError("内容不能超过 200 字");
+  requireString(ideaId, "ideaId");
+  const trimmedContent = validateIdeaContent(content);
 
   const idea = await prisma.blindBoxIdea.findUnique({ where: { id: ideaId } });
   if (!idea) throw new ApiError("想法不存在", 404);
@@ -69,7 +62,7 @@ export const PUT = apiHandler(async (req) => {
 
   const updated = await prisma.blindBoxIdea.update({
     where: { id: ideaId },
-    data: { content: content.trim() },
+    data: { content: trimmedContent },
   });
 
   return NextResponse.json({ id: updated.id, content: updated.content });
@@ -79,7 +72,7 @@ export const DELETE = apiHandler(async (req) => {
   const { ideaId, userId } = await req.json();
 
   requireUserId(userId);
-  if (!ideaId) throw new ApiError("缺少 ideaId");
+  requireString(ideaId, "ideaId");
 
   const idea = await prisma.blindBoxIdea.findUnique({ where: { id: ideaId } });
   if (!idea) throw new ApiError("想法不存在", 404);