fix avatar serving using readFile instead of stream

packages/api/src/routes/avatars.ts

@@ -1,6 +1,6 @@
 import { FastifyInstance } from "fastify";
-import { existsSync, mkdirSync, createReadStream } from "node:fs";
-import { unlink, writeFile, realpath } from "node:fs/promises";
+import { existsSync, mkdirSync } from "node:fs";
+import { unlink, writeFile, realpath, readFile } from "node:fs/promises";
 import { resolve, extname, sep } from "node:path";
 import { randomBytes } from "node:crypto";
 import prisma from "../lib/prisma.js";
@@ -172,11 +172,13 @@ export default async function avatarRoutes(app: FastifyInstance) {
         ".png": "image/png", ".webp": "image/webp",
       };
 
+      const buf = await readFile(realFile);
       reply
         .header("Content-Type", mimeMap[ext] || "application/octet-stream")
+        .header("Content-Length", buf.length)
         .header("Cache-Control", "public, max-age=3600, stale-while-revalidate=86400")
         .header("X-Content-Type-Options", "nosniff")
-        .send(createReadStream(filePath));
+        .send(buf);
     }
   );
 }