docs: update api-reference project for v2 (#7307)

* remove everything v1 and make v2 default

* move main v2 rewrites to book

* move rewrites to book + other fixes

www/apps/api-reference/app/api/download/[area]/route.ts

@@ -1,7 +1,6 @@
 import { existsSync, readFileSync } from "fs"
 import { NextResponse } from "next/server"
 import path from "path"
-import { Version } from "../../../../types/openapi"
 
 type DownloadParams = {
   params: {
@@ -10,16 +9,8 @@ type DownloadParams = {
 }
 
 export function GET(request: Request, { params }: DownloadParams) {
-  const { searchParams } = new URL(request.url)
   const { area } = params
-  const version =
-    process.env.NEXT_PUBLIC_VERSIONING === "true"
-      ? (searchParams.get("version") as Version) || "1"
-      : "1"
-  const filePath = path.join(
-    process.cwd(),
-    `${version === "1" ? "specs" : "specs-v2"}/${area}/openapi.full.yaml`
-  )
+  const filePath = path.join(process.cwd(), "specs", area, "openapi.full.yaml")
 
   if (!existsSync(filePath)) {
     return new NextResponse(null, {