fix: remove functions block from vercel.json to fix pre-build validation error

The `functions` block pattern `api/index.js` fails Vercel's pre-build
validation because the file is generated during the build step (by
bundle-api.mjs), not available beforehand.

The in-code `export const config` in server/index.ts already configures
memory and maxDuration — Vercel's @vercel/node runtime picks it up from
the deployed function bundle without any vercel.json pattern matching.

Also reverts the rewrite destination to `/api` (the auto-detected route
for api/index.js) instead of `/api/index.js` (a file path that doesn't
map to a Vercel route).

Agent-Logs-Url: https://github.com/objectstack-ai/framework/sessions/16819ebf-4d21-4ae9-892d-8c1593b21504

Co-authored-by: hotlong <50353452+hotlong@users.noreply.github.com>

Author: Copilot

CHANGELOG.md

@@ -11,9 +11,10 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 - **Studio Vercel API routes returning HTML instead of JSON** — Updated
   `apps/studio/vercel.json` to correctly configure Vercel serverless functions.
   Added `outputDirectory: "public"` so Vercel serves static files from the
-  correct directory, declared `api/index.js` in the `functions` block so Vercel
-  recognises it as a serverless function, and changed the API rewrite destination
-  from `/api` to `/api/index.js` to route requests to the bundled handler.
+  correct directory and the `api/` directory is auto-detected for serverless
+  functions.  Removed the `functions` block (the in-code `export const config`
+  in `server/index.ts` already configures memory/maxDuration without pre-build
+  file-pattern validation errors).
 - **Studio CORS error on Vercel temporary/preview domains** — Added Hono CORS
   middleware to `apps/studio/server/index.ts` so the serverless function returns
   correct `Access-Control-Allow-Origin` headers for cross-origin requests.

apps/studio/vercel.json

@@ -4,12 +4,6 @@
   "installCommand": "cd ../.. && pnpm install",
   "buildCommand": "bash scripts/build-vercel.sh",
   "outputDirectory": "public",
-  "functions": {
-    "api/index.js": {
-      "memory": 1024,
-      "maxDuration": 60
-    }
-  },
   "build": {
     "env": {
       "VITE_RUNTIME_MODE": "server",
@@ -25,7 +19,7 @@
     }
   ],
   "rewrites": [
-    { "source": "/api/(.*)", "destination": "/api/index.js" },
+    { "source": "/api/(.*)", "destination": "/api" },
     { "source": "/((?!api/).*)", "destination": "/index.html" }
   ]
 }