fix: load .env before imports and improve dev startup

Co-authored-by: Cursor <cursoragent@cursor.com>

server/index.ts

@@ -1,12 +1,11 @@
+import "./load-env.js";
 import cors from "cors";
-import dotenv from "dotenv";
 import express from "express";
 import path from "node:path";
 import { fileURLToPath } from "node:url";
+import { MulterError } from "multer";
 import { buildsRouter } from "./routes/builds.js";
 
-dotenv.config({ path: path.resolve(path.dirname(fileURLToPath(import.meta.url)), "../.env") });
-
 const app = express();
 const port = Number(process.env.PORT ?? "3001");
 
@@ -19,6 +18,28 @@ app.get("/api/health", (_req, res) => {
 
 app.use("/api/builds", buildsRouter);
 
+app.use((err: unknown, _req: express.Request, res: express.Response, next: express.NextFunction) => {
+  if (res.headersSent) {
+    next(err);
+    return;
+  }
+
+  if (err instanceof MulterError) {
+    const status = err.code === "LIMIT_FILE_SIZE" ? 413 : 400;
+    res.status(status).json({ error: err.message });
+    return;
+  }
+
+  if (err instanceof Error) {
+    console.error(err);
+    res.status(500).json({ error: err.message });
+    return;
+  }
+
+  console.error(err);
+  res.status(500).json({ error: "Internal server error" });
+});
+
 const webDist = path.resolve(path.dirname(fileURLToPath(import.meta.url)), "../web/dist");
 app.use(express.static(webDist));
 app.get("*", (_req, res, next) => {
@@ -31,6 +52,6 @@ app.get("*", (_req, res, next) => {
   });
 });
 
-app.listen(port, () => {
-  console.log(`Web2App server listening on http://localhost:${port}`);
+app.listen(port, "127.0.0.1", () => {
+  console.log(`Web2App server listening on http://127.0.0.1:${port}`);
 });